diff --git a/src/init.cpp b/src/init.cpp
index 664eb5628..51018cbf0 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -1,3048 +1,3058 @@
 // Copyright (c) 2009-2010 Satoshi Nakamoto
 // Copyright (c) 2009-2018 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #if defined(HAVE_CONFIG_H)
 #include <config/bitcoin-config.h>
 #endif
 
 #include <init.h>
 
 #include <addrman.h>
 #include <amount.h>
 #include <avalanche/avalanche.h>
 #include <avalanche/processor.h>
 #include <avalanche/proof.h> // For AVALANCHE_LEGACY_PROOF_DEFAULT
 #include <avalanche/validation.h>
 #include <banman.h>
 #include <blockdb.h>
 #include <blockfilter.h>
 #include <chain.h>
 #include <chainparams.h>
 #include <checkpoints.h>
 #include <compat/sanity.h>
 #include <config.h>
 #include <consensus/validation.h>
 #include <currencyunit.h>
 #include <flatfile.h>
 #include <fs.h>
 #include <hash.h>
 #include <httprpc.h>
 #include <httpserver.h>
 #include <index/blockfilterindex.h>
 #include <index/txindex.h>
 #include <interfaces/chain.h>
 #include <interfaces/node.h>
 #include <key.h>
 #include <miner.h>
 #include <net.h>
 #include <net_permissions.h>
 #include <net_processing.h>
 #include <netbase.h>
 #include <network.h>
 #include <node/context.h>
 #include <node/ui_interface.h>
 #include <policy/mempool.h>
 #include <policy/policy.h>
 #include <policy/settings.h>
 #include <rpc/blockchain.h>
 #include <rpc/register.h>
 #include <rpc/server.h>
 #include <rpc/util.h>
 #include <scheduler.h>
 #include <script/scriptcache.h>
 #include <script/sigcache.h>
 #include <script/standard.h>
 #include <shutdown.h>
 #include <sync.h>
 #include <timedata.h>
 #include <torcontrol.h>
 #include <txdb.h>
 #include <txmempool.h>
 #include <util/asmap.h>
 #include <util/check.h>
 #include <util/moneystr.h>
 #include <util/string.h>
 #include <util/threadnames.h>
 #include <util/translation.h>
 #include <validation.h>
 #include <validationinterface.h>
 #include <walletinitinterface.h>
 
 #include <boost/algorithm/string/replace.hpp>
 #include <boost/signals2/signal.hpp>
 #include <boost/thread/thread.hpp>
 
 #if ENABLE_ZMQ
 #include <zmq/zmqabstractnotifier.h>
 #include <zmq/zmqnotificationinterface.h>
 #include <zmq/zmqrpc.h>
 #endif
 
 #ifndef WIN32
 #include <attributes.h>
 #include <cerrno>
 #include <csignal>
 #include <sys/stat.h>
 #endif
 #include <cstdint>
 #include <cstdio>
 #include <functional>
 #include <set>
 
 static const bool DEFAULT_PROXYRANDOMIZE = true;
 static const bool DEFAULT_REST_ENABLE = false;
 static const bool DEFAULT_STOPAFTERBLOCKIMPORT = false;
 
 #ifdef WIN32
 // Win32 LevelDB doesn't use filedescriptors, and the ones used for accessing
 // block files don't count towards the fd_set size limit anyway.
 #define MIN_CORE_FILEDESCRIPTORS 0
 #else
 #define MIN_CORE_FILEDESCRIPTORS 150
 #endif
 
 static const char *DEFAULT_ASMAP_FILENAME = "ip_asn.map";
 
 /**
  * The PID file facilities.
  */
 static const char *BITCOIN_PID_FILENAME = "bitcoind.pid";
 
 static fs::path GetPidFile(const ArgsManager &args) {
     return AbsPathForConfigVal(
         fs::path(args.GetArg("-pid", BITCOIN_PID_FILENAME)));
 }
 
 NODISCARD static bool CreatePidFile(const ArgsManager &args) {
     fsbridge::ofstream file{GetPidFile(args)};
     if (file) {
 #ifdef WIN32
         tfm::format(file, "%d\n", GetCurrentProcessId());
 #else
         tfm::format(file, "%d\n", getpid());
 #endif
         return true;
     } else {
         return InitError(strprintf(_("Unable to create the PID file '%s': %s"),
                                    GetPidFile(args).string(),
                                    std::strerror(errno)));
     }
 }
 
 //////////////////////////////////////////////////////////////////////////////
 //
 // Shutdown
 //
 
 //
 // Thread management and startup/shutdown:
 //
 // The network-processing threads are all part of a thread group created by
 // AppInit() or the Qt main() function.
 //
 // A clean exit happens when StartShutdown() or the SIGTERM signal handler sets
 // fRequestShutdown, which makes main thread's WaitForShutdown() interrupts the
 // thread group.
 // And then, WaitForShutdown() makes all other on-going threads in the thread
 // group join the main thread.
 // Shutdown() is then called to clean up database connections, and stop other
 // threads that should only be stopped after the main network-processing threads
 // have exited.
 //
 // Shutdown for Qt is very similar, only it uses a QTimer to detect
 // ShutdownRequested() getting set, and then does the normal Qt shutdown thing.
 //
 
 static std::unique_ptr<ECCVerifyHandle> globalVerifyHandle;
 
 static std::thread g_load_block;
 
 static boost::thread_group threadGroup;
 
 void Interrupt(NodeContext &node) {
     InterruptHTTPServer();
     InterruptHTTPRPC();
     InterruptRPC();
     InterruptREST();
     InterruptTorControl();
     InterruptMapPort();
     if (g_avalanche) {
         // Avalanche needs to be stopped before we interrupt the thread group as
         // the scheduler will stop working then.
         g_avalanche->stopEventLoop();
     }
     if (node.connman) {
         node.connman->Interrupt();
     }
     if (g_txindex) {
         g_txindex->Interrupt();
     }
     ForEachBlockFilterIndex([](BlockFilterIndex &index) { index.Interrupt(); });
 }
 
 void Shutdown(NodeContext &node) {
     static Mutex g_shutdown_mutex;
     TRY_LOCK(g_shutdown_mutex, lock_shutdown);
     if (!lock_shutdown) {
         return;
     }
     LogPrintf("%s: In progress...\n", __func__);
     Assert(node.args);
 
     /// Note: Shutdown() must be able to handle cases in which initialization
     /// failed part of the way, for example if the data directory was found to
     /// be locked. Be sure that anything that writes files or flushes caches
     /// only does this if the respective module was initialized.
     util::ThreadRename("shutoff");
     if (node.mempool) {
         node.mempool->AddTransactionsUpdated(1);
     }
 
     StopHTTPRPC();
     StopREST();
     StopRPC();
     StopHTTPServer();
     for (const auto &client : node.chain_clients) {
         client->flush();
     }
     StopMapPort();
 
     // Because avalanche and the network depend on each other, it is important
     // to shut them down in this order:
     // 1. Stop avalanche event loop.
     // 2. Shutdown network processing.
     // 3. Destroy avalanche::Processor.
     // 4. Destroy CConnman
     if (g_avalanche) {
         g_avalanche->stopEventLoop();
     }
 
     // Because these depend on each-other, we make sure that neither can be
     // using the other before destroying them.
     if (node.peerman) {
         UnregisterValidationInterface(node.peerman.get());
     }
     // Follow the lock order requirements:
     // * CheckForStaleTipAndEvictPeers locks cs_main before indirectly calling
     //   GetExtraOutboundCount which locks cs_vNodes.
     // * ProcessMessage locks cs_main and g_cs_orphans before indirectly calling
     //   ForEachNode which locks cs_vNodes.
     // * CConnman::Stop calls DeleteNode, which calls FinalizeNode, which locks
     //   cs_main and calls EraseOrphansFor, which locks g_cs_orphans.
     //
     // Thus the implicit locking order requirement is:
     // (1) cs_main, (2) g_cs_orphans, (3) cs_vNodes.
     if (node.connman) {
         node.connman->StopThreads();
         LOCK2(::cs_main, ::g_cs_orphans);
         node.connman->StopNodes();
     }
 
     StopTorControl();
 
     // After everything has been shut down, but before things get flushed, stop
     // the CScheduler/checkqueue, threadGroup and load block thread.
     if (node.scheduler) {
         node.scheduler->stop();
     }
     if (g_load_block.joinable()) {
         g_load_block.join();
     }
     threadGroup.interrupt_all();
     threadGroup.join_all();
 
     // After the threads that potentially access these pointers have been
     // stopped, destruct and reset all to nullptr.
     node.peerman.reset();
 
     // Destroy various global instances
     g_avalanche.reset();
     node.connman.reset();
     node.banman.reset();
 
     if (node.mempool && node.mempool->IsLoaded() &&
         node.args->GetArg("-persistmempool", DEFAULT_PERSIST_MEMPOOL)) {
         DumpMempool(*node.mempool);
     }
 
     // FlushStateToDisk generates a ChainStateFlushed callback, which we should
     // avoid missing
     if (node.chainman) {
         LOCK(cs_main);
         for (CChainState *chainstate : node.chainman->GetAll()) {
             if (chainstate->CanFlushToDisk()) {
                 chainstate->ForceFlushStateToDisk();
             }
         }
     }
 
     // After there are no more peers/RPC left to give us new data which may
     // generate CValidationInterface callbacks, flush them...
     GetMainSignals().FlushBackgroundCallbacks();
 
     // Stop and delete all indexes only after flushing background callbacks.
     if (g_txindex) {
         g_txindex->Stop();
         g_txindex.reset();
     }
     ForEachBlockFilterIndex([](BlockFilterIndex &index) { index.Stop(); });
     DestroyAllBlockFilterIndexes();
 
     // Any future callbacks will be dropped. This should absolutely be safe - if
     // missing a callback results in an unrecoverable situation, unclean
     // shutdown would too. The only reason to do the above flushes is to let the
     // wallet catch up with our current chain to avoid any strange pruning edge
     // cases and make next startup faster by avoiding rescan.
 
     if (node.chainman) {
         LOCK(cs_main);
         for (CChainState *chainstate : node.chainman->GetAll()) {
             if (chainstate->CanFlushToDisk()) {
                 chainstate->ForceFlushStateToDisk();
                 chainstate->ResetCoinsViews();
             }
         }
         pblocktree.reset();
     }
     for (const auto &client : node.chain_clients) {
         client->stop();
     }
 
 #if ENABLE_ZMQ
     if (g_zmq_notification_interface) {
         UnregisterValidationInterface(g_zmq_notification_interface);
         delete g_zmq_notification_interface;
         g_zmq_notification_interface = nullptr;
     }
 #endif
 
     node.chain_clients.clear();
     UnregisterAllValidationInterfaces();
     GetMainSignals().UnregisterBackgroundSignalScheduler();
     globalVerifyHandle.reset();
     ECC_Stop();
     node.mempool.reset();
     node.chainman = nullptr;
     node.scheduler.reset();
 
     try {
         if (!fs::remove(GetPidFile(*node.args))) {
             LogPrintf("%s: Unable to remove PID file: File does not exist\n",
                       __func__);
         }
     } catch (const fs::filesystem_error &e) {
         LogPrintf("%s: Unable to remove PID file: %s\n", __func__,
                   fsbridge::get_filesystem_error_message(e));
     }
 
     node.args = nullptr;
     LogPrintf("%s: done\n", __func__);
 }
 
 /**
  * Signal handlers are very limited in what they are allowed to do.
  * The execution context the handler is invoked in is not guaranteed,
  * so we restrict handler operations to just touching variables:
  */
 #ifndef WIN32
 static void HandleSIGTERM(int) {
     StartShutdown();
 }
 
 static void HandleSIGHUP(int) {
     LogInstance().m_reopen_file = true;
 }
 #else
 static BOOL WINAPI consoleCtrlHandler(DWORD dwCtrlType) {
     StartShutdown();
     Sleep(INFINITE);
     return true;
 }
 #endif
 
 #ifndef WIN32
 static void registerSignalHandler(int signal, void (*handler)(int)) {
     struct sigaction sa;
     sa.sa_handler = handler;
     sigemptyset(&sa.sa_mask);
     sa.sa_flags = 0;
     sigaction(signal, &sa, NULL);
 }
 #endif
 
 static boost::signals2::connection rpc_notify_block_change_connection;
 static void OnRPCStarted() {
     rpc_notify_block_change_connection = uiInterface.NotifyBlockTip_connect(
         std::bind(RPCNotifyBlockChange, std::placeholders::_2));
 }
 
 static void OnRPCStopped() {
     rpc_notify_block_change_connection.disconnect();
     RPCNotifyBlockChange(nullptr);
     g_best_block_cv.notify_all();
     LogPrint(BCLog::RPC, "RPC stopped.\n");
 }
 
 void SetupServerArgs(NodeContext &node) {
     assert(!node.args);
     node.args = &gArgs;
     ArgsManager &argsman = *node.args;
 
     SetupHelpOptions(argsman);
     SetupCurrencyUnitOptions(argsman);
     // server-only for now
     argsman.AddArg("-help-debug",
                    "Print help message with debugging options and exit", false,
                    OptionsCategory::DEBUG_TEST);
 
     const auto defaultBaseParams =
         CreateBaseChainParams(CBaseChainParams::MAIN);
     const auto testnetBaseParams =
         CreateBaseChainParams(CBaseChainParams::TESTNET);
     const auto regtestBaseParams =
         CreateBaseChainParams(CBaseChainParams::REGTEST);
     const auto defaultChainParams = CreateChainParams(CBaseChainParams::MAIN);
     const auto testnetChainParams =
         CreateChainParams(CBaseChainParams::TESTNET);
     const auto regtestChainParams =
         CreateChainParams(CBaseChainParams::REGTEST);
 
     // Hidden Options
     std::vector<std::string> hidden_args = {
         "-dbcrashratio", "-forcecompactdb", "-parkdeepreorg",
         "-automaticunparking", "-replayprotectionactivationtime",
         "-enableminerfund",
         // GUI args. These will be overwritten by SetupUIArgs for the GUI
         "-allowselfsignedrootcertificates", "-choosedatadir", "-lang=<lang>",
         "-min", "-resetguisettings", "-rootcertificates=<file>", "-splash",
         "-uiplatform",
         // TODO remove after the November 2020 upgrade
         "-axionactivationtime"};
 
     // Set all of the args and their help
     // When adding new options to the categories, please keep and ensure
     // alphabetical ordering. Do not translate _(...) -help-debug options, Many
     // technical terms, and only a very small audience, so is unnecessary stress
     // to translators.
     argsman.AddArg("-version", "Print version and exit", ArgsManager::ALLOW_ANY,
                    OptionsCategory::OPTIONS);
 #if defined(HAVE_SYSTEM)
     argsman.AddArg(
         "-alertnotify=<cmd>",
         "Execute command when a relevant alert is received or we see "
         "a really long fork (%s in cmd is replaced by message)",
         ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
 #endif
     argsman.AddArg(
         "-assumevalid=<hex>",
         strprintf(
             "If this block is in the chain assume that it and its ancestors "
             "are valid and potentially skip their script verification (0 to "
             "verify all, default: %s, testnet: %s)",
             defaultChainParams->GetConsensus().defaultAssumeValid.GetHex(),
             testnetChainParams->GetConsensus().defaultAssumeValid.GetHex()),
         ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     argsman.AddArg("-blocksdir=<dir>",
                    "Specify directory to hold blocks subdirectory for *.dat "
                    "files (default: <datadir>)",
                    ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
 #if defined(HAVE_SYSTEM)
     argsman.AddArg("-blocknotify=<cmd>",
                    "Execute command when the best block changes (%s in cmd is "
                    "replaced by block hash)",
                    ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
 #endif
     argsman.AddArg("-blockreconstructionextratxn=<n>",
                    strprintf("Extra transactions to keep in memory for compact "
                              "block reconstructions (default: %u)",
                              DEFAULT_BLOCK_RECONSTRUCTION_EXTRA_TXN),
                    ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     argsman.AddArg(
         "-blocksonly",
         strprintf("Whether to reject transactions from network peers.  "
                   "Automatic broadcast and rebroadcast of any transactions "
                   "from inbound peers is disabled, unless the peer has the "
                   "'forcerelay' permission. RPC transactions are"
                   " not affected. (default: %u)",
                   DEFAULT_BLOCKSONLY),
         ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     argsman.AddArg(
         "-conf=<file>",
         strprintf("Specify path to read-only configuration file. Relative "
                   "paths will be prefixed by datadir location. (default: %s)",
                   BITCOIN_CONF_FILENAME),
         ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     argsman.AddArg("-datadir=<dir>", "Specify data directory",
                    ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     argsman.AddArg(
         "-dbbatchsize",
         strprintf("Maximum database write batch size in bytes (default: %u)",
                   DEFAULT_DB_BATCH_SIZE),
         ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY,
         OptionsCategory::OPTIONS);
     argsman.AddArg(
         "-dbcache=<n>",
         strprintf("Set database cache size in MiB (%d to %d, default: %d)",
                   MIN_DB_CACHE_MB, MAX_DB_CACHE_MB, DEFAULT_DB_CACHE_MB),
         ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     argsman.AddArg(
         "-debuglogfile=<file>",
         strprintf("Specify location of debug log file. Relative paths "
                   "will be prefixed by a net-specific datadir "
                   "location. (0 to disable; default: %s)",
                   DEFAULT_DEBUGLOGFILE),
         ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     argsman.AddArg("-feefilter",
                    strprintf("Tell other nodes to filter invs to us by our "
                              "mempool min fee (default: %d)",
                              DEFAULT_FEEFILTER),
                    ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY,
                    OptionsCategory::OPTIONS);
     argsman.AddArg(
         "-finalizationdelay=<n>",
         strprintf("Set the minimum amount of time to wait between a "
                   "block header reception and the block finalization. "
                   "Unit is seconds (default: %d)",
                   DEFAULT_MIN_FINALIZATION_DELAY),
         ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     argsman.AddArg(
         "-includeconf=<file>",
         "Specify additional configuration file, relative to the -datadir path "
         "(only useable from configuration file, not command line)",
         ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     argsman.AddArg("-maxreorgdepth=<n>",
                    strprintf("Configure at what depth blocks are considered "
                              "final (default: %d). Use -1 to disable.",
                              DEFAULT_MAX_REORG_DEPTH),
                    ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     argsman.AddArg("-loadblock=<file>",
                    "Imports blocks from external file on startup",
                    ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     argsman.AddArg("-maxmempool=<n>",
                    strprintf("Keep the transaction memory pool below <n> "
                              "megabytes (default: %u)",
                              DEFAULT_MAX_MEMPOOL_SIZE),
                    ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     argsman.AddArg("-maxorphantx=<n>",
                    strprintf("Keep at most <n> unconnectable transactions in "
                              "memory (default: %u)",
                              DEFAULT_MAX_ORPHAN_TRANSACTIONS),
                    ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     argsman.AddArg("-mempoolexpiry=<n>",
                    strprintf("Do not keep transactions in the mempool longer "
                              "than <n> hours (default: %u)",
                              DEFAULT_MEMPOOL_EXPIRY),
                    ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     argsman.AddArg(
         "-minimumchainwork=<hex>",
         strprintf(
             "Minimum work assumed to exist on a valid chain in hex "
             "(default: %s, testnet: %s)",
             defaultChainParams->GetConsensus().nMinimumChainWork.GetHex(),
             testnetChainParams->GetConsensus().nMinimumChainWork.GetHex()),
         ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY,
         OptionsCategory::OPTIONS);
     argsman.AddArg(
         "-par=<n>",
         strprintf("Set the number of script verification threads (%u to %d, 0 "
                   "= auto, <0 = leave that many cores free, default: %d)",
                   -GetNumCores(), MAX_SCRIPTCHECK_THREADS,
                   DEFAULT_SCRIPTCHECK_THREADS),
         ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     argsman.AddArg("-persistmempool",
                    strprintf("Whether to save the mempool on shutdown and load "
                              "on restart (default: %u)",
                              DEFAULT_PERSIST_MEMPOOL),
                    ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     argsman.AddArg(
         "-pid=<file>",
         strprintf("Specify pid file. Relative paths will be prefixed "
                   "by a net-specific datadir location. (default: %s)",
                   BITCOIN_PID_FILENAME),
         ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     argsman.AddArg(
         "-prune=<n>",
         strprintf("Reduce storage requirements by enabling pruning (deleting) "
                   "of old blocks. This allows the pruneblockchain RPC to be "
                   "called to delete specific blocks, and enables automatic "
                   "pruning of old blocks if a target size in MiB is provided. "
                   "This mode is incompatible with -txindex and -rescan. "
                   "Warning: Reverting this setting requires re-downloading the "
                   "entire blockchain. (default: 0 = disable pruning blocks, 1 "
                   "= allow manual pruning via RPC, >=%u = automatically prune "
                   "block files to stay under the specified target size in MiB)",
                   MIN_DISK_SPACE_FOR_BLOCK_FILES / 1024 / 1024),
         ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     argsman.AddArg(
         "-reindex-chainstate",
         "Rebuild chain state from the currently indexed blocks. When "
         "in pruning mode or if blocks on disk might be corrupted, use "
         "full -reindex instead.",
         ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     argsman.AddArg(
         "-reindex",
         "Rebuild chain state and block index from the blk*.dat files on disk",
         ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     argsman.AddArg(
         "-settings=<file>",
         strprintf(
             "Specify path to dynamic settings data file. Can be disabled with "
             "-nosettings. File is written at runtime and not meant to be "
             "edited by users (use %s instead for custom settings). Relative "
             "paths will be prefixed by datadir location. (default: %s)",
             BITCOIN_CONF_FILENAME, BITCOIN_SETTINGS_FILENAME),
         ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
 #ifndef WIN32
     argsman.AddArg(
         "-sysperms",
         "Create new files with system default permissions, instead of umask "
         "077 (only effective with disabled wallet functionality)",
         ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
 #else
     hidden_args.emplace_back("-sysperms");
 #endif
     argsman.AddArg("-txindex",
                    strprintf("Maintain a full transaction index, used by the "
                              "getrawtransaction rpc call (default: %d)",
                              DEFAULT_TXINDEX),
                    ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     argsman.AddArg(
         "-blockfilterindex=<type>",
         strprintf("Maintain an index of compact filters by block "
                   "(default: %s, values: %s).",
                   DEFAULT_BLOCKFILTERINDEX, ListBlockFilterTypes()) +
             " If <type> is not supplied or if <type> = 1, indexes for "
             "all known types are enabled.",
         ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     argsman.AddArg(
         "-usecashaddr",
         "Use Cash Address for destination encoding instead of base58 "
         "(activate by default on Jan, 14)",
         ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
 
     argsman.AddArg(
         "-addnode=<ip>",
         "Add a node to connect to and attempt to keep the connection "
         "open (see the `addnode` RPC command help for more info)",
         ArgsManager::ALLOW_ANY | ArgsManager::NETWORK_ONLY,
         OptionsCategory::CONNECTION);
     argsman.AddArg("-asmap=<file>",
                    strprintf("Specify asn mapping used for bucketing of the "
                              "peers (default: %s). Relative paths will be "
                              "prefixed by the net-specific datadir location.",
                              DEFAULT_ASMAP_FILENAME),
                    ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg("-bantime=<n>",
                    strprintf("Default duration (in seconds) of manually "
                              "configured bans (default: %u)",
                              DEFAULT_MISBEHAVING_BANTIME),
                    ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg("-bind=<addr>",
                    "Bind to given address and always listen on it. Use "
                    "[host]:port notation for IPv6",
                    ArgsManager::ALLOW_ANY | ArgsManager::NETWORK_ONLY,
                    OptionsCategory::CONNECTION);
     argsman.AddArg(
         "-connect=<ip>",
         "Connect only to the specified node(s); -connect=0 disables automatic "
         "connections (the rules for this peer are the same as for -addnode)",
         ArgsManager::ALLOW_ANY | ArgsManager::NETWORK_ONLY,
         OptionsCategory::CONNECTION);
     argsman.AddArg(
         "-discover",
         "Discover own IP addresses (default: 1 when listening and no "
         "-externalip or -proxy)",
         ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg("-dns",
                    strprintf("Allow DNS lookups for -addnode, -seednode and "
                              "-connect (default: %d)",
                              DEFAULT_NAME_LOOKUP),
                    ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg(
         "-dnsseed",
         "Query for peer addresses via DNS lookup, if low on addresses "
         "(default: 1 unless -connect used)",
         ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
 
     argsman.AddArg("-externalip=<ip>", "Specify your own public address",
                    ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg(
         "-forcednsseed",
         strprintf(
             "Always query for peer addresses via DNS lookup (default: %d)",
             DEFAULT_FORCEDNSSEED),
         ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg("-overridednsseed",
                    "If set, only use the specified DNS seed when "
                    "querying for peer addresses via DNS lookup.",
                    ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg(
         "-listen",
         "Accept connections from outside (default: 1 if no -proxy or -connect)",
         ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg(
         "-listenonion",
         strprintf("Automatically create Tor onion service (default: %d)",
                   DEFAULT_LISTEN_ONION),
         ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg(
         "-maxconnections=<n>",
         strprintf("Maintain at most <n> connections to peers. The effective "
                   "limit depends on system limitations and might be lower than "
                   "the specified value (default: %u)",
                   DEFAULT_MAX_PEER_CONNECTIONS),
         ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg("-maxreceivebuffer=<n>",
                    strprintf("Maximum per-connection receive buffer, <n>*1000 "
                              "bytes (default: %u)",
                              DEFAULT_MAXRECEIVEBUFFER),
                    ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg(
         "-maxsendbuffer=<n>",
         strprintf(
             "Maximum per-connection send buffer, <n>*1000 bytes (default: %u)",
             DEFAULT_MAXSENDBUFFER),
         ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg(
         "-maxtimeadjustment",
         strprintf("Maximum allowed median peer time offset adjustment. Local "
                   "perspective of time may be influenced by peers forward or "
                   "backward by this amount. (default: %u seconds)",
                   DEFAULT_MAX_TIME_ADJUSTMENT),
         ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg("-onion=<ip:port>",
                    strprintf("Use separate SOCKS5 proxy to reach peers via Tor "
                              "onion services (default: %s)",
                              "-proxy"),
                    ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg(
         "-onlynet=<net>",
         "Make outgoing connections only through network <net> (ipv4, ipv6 or "
         "onion). Incoming connections are not affected by this option. This "
         "option can be specified multiple times to allow multiple networks.",
         ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg("-peerbloomfilters",
                    strprintf("Support filtering of blocks and transaction with "
                              "bloom filters (default: %d)",
                              DEFAULT_PEERBLOOMFILTERS),
                    ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg(
         "-peerblockfilters",
         strprintf(
             "Serve compact block filters to peers per BIP 157 (default: %u)",
             DEFAULT_PEERBLOCKFILTERS),
         ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg("-permitbaremultisig",
                    strprintf("Relay non-P2SH multisig (default: %d)",
                              DEFAULT_PERMIT_BAREMULTISIG),
                    ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg("-port=<port>",
                    strprintf("Listen for connections on <port> (default: %u, "
                              "testnet: %u, regtest: %u)",
                              defaultChainParams->GetDefaultPort(),
                              testnetChainParams->GetDefaultPort(),
                              regtestChainParams->GetDefaultPort()),
                    ArgsManager::ALLOW_ANY | ArgsManager::NETWORK_ONLY,
                    OptionsCategory::CONNECTION);
     argsman.AddArg("-proxy=<ip:port>", "Connect through SOCKS5 proxy",
                    ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg(
         "-proxyrandomize",
         strprintf("Randomize credentials for every proxy connection. "
                   "This enables Tor stream isolation (default: %d)",
                   DEFAULT_PROXYRANDOMIZE),
         ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg(
         "-seednode=<ip>",
         "Connect to a node to retrieve peer addresses, and disconnect",
         ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     gArgs.AddArg("-networkactive",
                  "Enable all P2P network activity (default: 1). Can be changed "
                  "by the setnetworkactive RPC command",
                  ArgsManager::ALLOW_BOOL, OptionsCategory::CONNECTION);
     argsman.AddArg("-timeout=<n>",
                    strprintf("Specify connection timeout in milliseconds "
                              "(minimum: 1, default: %d)",
                              DEFAULT_CONNECT_TIMEOUT),
                    ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg(
         "-peertimeout=<n>",
         strprintf("Specify p2p connection timeout in seconds. This option "
                   "determines the amount of time a peer may be inactive before "
                   "the connection to it is dropped. (minimum: 1, default: %d)",
                   DEFAULT_PEER_CONNECT_TIMEOUT),
         true, OptionsCategory::CONNECTION);
     argsman.AddArg(
         "-torcontrol=<ip>:<port>",
         strprintf(
             "Tor control port to use if onion listening enabled (default: %s)",
             DEFAULT_TOR_CONTROL),
         ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg("-torpassword=<pass>",
                    "Tor control port password (default: empty)",
                    ArgsManager::ALLOW_ANY | ArgsManager::SENSITIVE,
                    OptionsCategory::CONNECTION);
 #ifdef USE_UPNP
 #if USE_UPNP
     argsman.AddArg("-upnp",
                    "Use UPnP to map the listening port (default: 1 when "
                    "listening and no -proxy)",
                    ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
 #else
     argsman.AddArg(
         "-upnp",
         strprintf("Use UPnP to map the listening port (default: %u)", 0),
         ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
 #endif
 #else
     hidden_args.emplace_back("-upnp");
 #endif
     argsman.AddArg(
         "-whitebind=<[permissions@]addr>",
         "Bind to the given address and add permission flags to the peers "
         "connecting to it."
         "Use [host]:port notation for IPv6. Allowed permissions: " +
             Join(NET_PERMISSIONS_DOC, ", ") +
             ". "
             "Specify multiple permissions separated by commas (default: "
             "download,noban,mempool,relay). Can be specified multiple times.",
         ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
 
     argsman.AddArg("-whitelist=<[permissions@]IP address or network>",
                    "Add permission flags to the peers connecting from the "
                    "given IP address (e.g. 1.2.3.4) or CIDR-notated network "
                    "(e.g. 1.2.3.0/24). "
                    "Uses the same permissions as -whitebind. Can be specified "
                    "multiple times.",
                    ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg(
         "-maxuploadtarget=<n>",
         strprintf("Tries to keep outbound traffic under the given target (in "
                   "MiB per 24h). Limit does not apply to peers with 'download' "
                   "permission. 0 = no limit (default: %d)",
                   DEFAULT_MAX_UPLOAD_TARGET),
         ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
 
     g_wallet_init_interface.AddWalletOptions(argsman);
 
 #if ENABLE_ZMQ
     argsman.AddArg("-zmqpubhashblock=<address>",
                    "Enable publish hash block in <address>",
                    ArgsManager::ALLOW_ANY, OptionsCategory::ZMQ);
     argsman.AddArg("-zmqpubhashtx=<address>",
                    "Enable publish hash transaction in <address>",
                    ArgsManager::ALLOW_ANY, OptionsCategory::ZMQ);
     argsman.AddArg("-zmqpubrawblock=<address>",
                    "Enable publish raw block in <address>",
                    ArgsManager::ALLOW_ANY, OptionsCategory::ZMQ);
     argsman.AddArg("-zmqpubrawtx=<address>",
                    "Enable publish raw transaction in <address>",
                    ArgsManager::ALLOW_ANY, OptionsCategory::ZMQ);
+    argsman.AddArg("-zmqpubsequence=<address>",
+                   "Enable publish hash block and tx sequence in <address>",
+                   ArgsManager::ALLOW_ANY, OptionsCategory::ZMQ);
     argsman.AddArg(
         "-zmqpubhashblockhwm=<n>",
         strprintf("Set publish hash block outbound message high water "
                   "mark (default: %d)",
                   CZMQAbstractNotifier::DEFAULT_ZMQ_SNDHWM),
         false, OptionsCategory::ZMQ);
     argsman.AddArg(
         "-zmqpubhashtxhwm=<n>",
         strprintf("Set publish hash transaction outbound message high "
                   "water mark (default: %d)",
                   CZMQAbstractNotifier::DEFAULT_ZMQ_SNDHWM),
         false, OptionsCategory::ZMQ);
     argsman.AddArg(
         "-zmqpubrawblockhwm=<n>",
         strprintf("Set publish raw block outbound message high water "
                   "mark (default: %d)",
                   CZMQAbstractNotifier::DEFAULT_ZMQ_SNDHWM),
         false, OptionsCategory::ZMQ);
     argsman.AddArg(
         "-zmqpubrawtxhwm=<n>",
         strprintf("Set publish raw transaction outbound message high "
                   "water mark (default: %d)",
                   CZMQAbstractNotifier::DEFAULT_ZMQ_SNDHWM),
         false, OptionsCategory::ZMQ);
+    argsman.AddArg("-zmqpubsequencehwm=<n>",
+                   strprintf("Set publish hash sequence message high water mark"
+                             " (default: %d)",
+                             CZMQAbstractNotifier::DEFAULT_ZMQ_SNDHWM),
+                   ArgsManager::ALLOW_ANY, OptionsCategory::ZMQ);
 #else
     hidden_args.emplace_back("-zmqpubhashblock=<address>");
     hidden_args.emplace_back("-zmqpubhashtx=<address>");
     hidden_args.emplace_back("-zmqpubrawblock=<address>");
     hidden_args.emplace_back("-zmqpubrawtx=<address>");
+    hidden_args.emplace_back("-zmqpubsequence=<n>");
     hidden_args.emplace_back("-zmqpubhashblockhwm=<n>");
     hidden_args.emplace_back("-zmqpubhashtxhwm=<n>");
     hidden_args.emplace_back("-zmqpubrawblockhwm=<n>");
     hidden_args.emplace_back("-zmqpubrawtxhwm=<n>");
+    hidden_args.emplace_back("-zmqpubsequencehwm=<n>");
 #endif
 
     argsman.AddArg(
         "-checkblocks=<n>",
         strprintf("How many blocks to check at startup (default: %u, 0 = all)",
                   DEFAULT_CHECKBLOCKS),
         ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY,
         OptionsCategory::DEBUG_TEST);
     argsman.AddArg("-checklevel=<n>",
                    strprintf("How thorough the block verification of "
                              "-checkblocks is: %s (0-4, default: %u)",
                              Join(CHECKLEVEL_DOC, ", "), DEFAULT_CHECKLEVEL),
                    ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY,
                    OptionsCategory::DEBUG_TEST);
     argsman.AddArg("-checkblockindex",
                    strprintf("Do a consistency check for the block tree, "
                              "chainstate, and other validation data structures "
                              "occasionally. (default: %u, regtest: %u)",
                              defaultChainParams->DefaultConsistencyChecks(),
                              regtestChainParams->DefaultConsistencyChecks()),
                    ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY,
                    OptionsCategory::DEBUG_TEST);
     argsman.AddArg(
         "-checkmempool=<n>",
         strprintf(
             "Run checks every <n> transactions (default: %u, regtest: %u)",
             defaultChainParams->DefaultConsistencyChecks(),
             regtestChainParams->DefaultConsistencyChecks()),
         ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY,
         OptionsCategory::DEBUG_TEST);
     argsman.AddArg("-checkpoints",
                    strprintf("Only accept block chain matching built-in "
                              "checkpoints (default: %d)",
                              DEFAULT_CHECKPOINTS_ENABLED),
                    ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY,
                    OptionsCategory::DEBUG_TEST);
     argsman.AddArg("-deprecatedrpc=<method>",
                    "Allows deprecated RPC method(s) to be used",
                    ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY,
                    OptionsCategory::DEBUG_TEST);
     argsman.AddArg("-dropmessagestest=<n>",
                    "Randomly drop 1 of every <n> network messages",
                    ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY,
                    OptionsCategory::DEBUG_TEST);
     argsman.AddArg(
         "-stopafterblockimport",
         strprintf("Stop running after importing blocks from disk (default: %d)",
                   DEFAULT_STOPAFTERBLOCKIMPORT),
         ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY,
         OptionsCategory::DEBUG_TEST);
     argsman.AddArg("-stopatheight",
                    strprintf("Stop running after reaching the given height in "
                              "the main chain (default: %u)",
                              DEFAULT_STOPATHEIGHT),
                    ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY,
                    OptionsCategory::DEBUG_TEST);
     argsman.AddArg(
         "-limitancestorcount=<n>",
         strprintf("Do not accept transactions if number of in-mempool "
                   "ancestors is <n> or more (default: %u)",
                   DEFAULT_ANCESTOR_LIMIT),
         ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY,
         OptionsCategory::DEBUG_TEST);
     argsman.AddArg(
         "-limitancestorsize=<n>",
         strprintf("Do not accept transactions whose size with all in-mempool "
                   "ancestors exceeds <n> kilobytes (default: %u)",
                   DEFAULT_ANCESTOR_SIZE_LIMIT),
         ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY,
         OptionsCategory::DEBUG_TEST);
     argsman.AddArg(
         "-limitdescendantcount=<n>",
         strprintf("Do not accept transactions if any ancestor would have <n> "
                   "or more in-mempool descendants (default: %u)",
                   DEFAULT_DESCENDANT_LIMIT),
         ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY,
         OptionsCategory::DEBUG_TEST);
     argsman.AddArg(
         "-limitdescendantsize=<n>",
         strprintf("Do not accept transactions if any ancestor would have more "
                   "than <n> kilobytes of in-mempool descendants (default: %u).",
                   DEFAULT_DESCENDANT_SIZE_LIMIT),
         ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY,
         OptionsCategory::DEBUG_TEST);
     argsman.AddArg("-addrmantest", "Allows to test address relay on localhost",
                    ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY,
                    OptionsCategory::DEBUG_TEST);
 
     argsman.AddArg("-debug=<category>",
                    strprintf("Output debugging information (default: %u, "
                              "supplying <category> is optional)",
                              0) +
                        ". " +
                        "If <category> is not supplied or if <category> = 1, "
                        "output all debugging information. <category> can be: " +
                        LogInstance().LogCategoriesString() + ".",
                    ArgsManager::ALLOW_ANY, OptionsCategory::DEBUG_TEST);
     argsman.AddArg(
         "-debugexclude=<category>",
         strprintf("Exclude debugging information for a category. Can be used "
                   "in conjunction with -debug=1 to output debug logs for all "
                   "categories except one or more specified categories."),
         ArgsManager::ALLOW_ANY, OptionsCategory::DEBUG_TEST);
     argsman.AddArg(
         "-logips",
         strprintf("Include IP addresses in debug output (default: %d)",
                   DEFAULT_LOGIPS),
         ArgsManager::ALLOW_ANY, OptionsCategory::DEBUG_TEST);
     argsman.AddArg(
         "-logtimestamps",
         strprintf("Prepend debug output with timestamp (default: %d)",
                   DEFAULT_LOGTIMESTAMPS),
         ArgsManager::ALLOW_ANY, OptionsCategory::DEBUG_TEST);
 #ifdef HAVE_THREAD_LOCAL
     argsman.AddArg(
         "-logthreadnames",
         strprintf(
             "Prepend debug output with name of the originating thread (only "
             "available on platforms supporting thread_local) (default: %u)",
             DEFAULT_LOGTHREADNAMES),
         ArgsManager::ALLOW_ANY, OptionsCategory::DEBUG_TEST);
 #else
     hidden_args.emplace_back("-logthreadnames");
 #endif
     argsman.AddArg(
         "-logtimemicros",
         strprintf("Add microsecond precision to debug timestamps (default: %d)",
                   DEFAULT_LOGTIMEMICROS),
         ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY,
         OptionsCategory::DEBUG_TEST);
     argsman.AddArg("-mocktime=<n>",
                    "Replace actual time with " + UNIX_EPOCH_TIME +
                        " (default: 0)",
                    ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY,
                    OptionsCategory::DEBUG_TEST);
     argsman.AddArg(
         "-maxsigcachesize=<n>",
         strprintf("Limit size of signature cache to <n> MiB (default: %u)",
                   DEFAULT_MAX_SIG_CACHE_SIZE),
         ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY,
         OptionsCategory::DEBUG_TEST);
     argsman.AddArg(
         "-maxscriptcachesize=<n>",
         strprintf("Limit size of script cache to <n> MiB (default: %u)",
                   DEFAULT_MAX_SCRIPT_CACHE_SIZE),
         ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY,
         OptionsCategory::DEBUG_TEST);
     argsman.AddArg("-maxtipage=<n>",
                    strprintf("Maximum tip age in seconds to consider node in "
                              "initial block download (default: %u)",
                              DEFAULT_MAX_TIP_AGE),
                    ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY,
                    OptionsCategory::DEBUG_TEST);
 
     argsman.AddArg(
         "-printtoconsole",
         "Send trace/debug info to console instead of debug.log file (default: "
         "1 when no -daemon. To disable logging to file, set debuglogfile=0)",
         ArgsManager::ALLOW_ANY, OptionsCategory::DEBUG_TEST);
     argsman.AddArg("-printpriority",
                    strprintf("Log transaction priority and fee per kB when "
                              "mining blocks (default: %d)",
                              DEFAULT_PRINTPRIORITY),
                    ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY,
                    OptionsCategory::DEBUG_TEST);
     argsman.AddArg(
         "-shrinkdebugfile",
         "Shrink debug.log file on client startup (default: 1 when no -debug)",
         ArgsManager::ALLOW_ANY, OptionsCategory::DEBUG_TEST);
 
     argsman.AddArg("-uacomment=<cmt>",
                    "Append comment to the user agent string",
                    ArgsManager::ALLOW_ANY, OptionsCategory::DEBUG_TEST);
     argsman.AddArg("-uaclientname=<clientname>", "Set user agent client name",
                    ArgsManager::ALLOW_ANY, OptionsCategory::DEBUG_TEST);
     argsman.AddArg("-uaclientversion=<clientversion>",
                    "Set user agent client version", ArgsManager::ALLOW_ANY,
                    OptionsCategory::DEBUG_TEST);
 
     SetupChainParamsBaseOptions(argsman);
 
     argsman.AddArg(
         "-acceptnonstdtxn",
         strprintf(
             "Relay and mine \"non-standard\" transactions (%sdefault: %u)",
             "testnet/regtest only; ", defaultChainParams->RequireStandard()),
         ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY,
         OptionsCategory::NODE_RELAY);
     argsman.AddArg("-excessiveblocksize=<n>",
                    strprintf("Do not accept blocks larger than this limit, in "
                              "bytes (default: %d)",
                              DEFAULT_MAX_BLOCK_SIZE),
                    ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY,
                    OptionsCategory::NODE_RELAY);
     const auto &ticker = Currency::get().ticker;
     argsman.AddArg(
         "-dustrelayfee=<amt>",
         strprintf("Fee rate (in %s/kB) used to define dust, the value of an "
                   "output such that it will cost about 1/3 of its value in "
                   "fees at this fee rate to spend it. (default: %s)",
                   ticker, FormatMoney(DUST_RELAY_TX_FEE)),
         ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY,
         OptionsCategory::NODE_RELAY);
 
     argsman.AddArg("-bytespersigop",
                    strprintf("Equivalent bytes per sigop in transactions for "
                              "relay and mining (default: %u)",
                              DEFAULT_BYTES_PER_SIGOP),
                    ArgsManager::ALLOW_ANY, OptionsCategory::NODE_RELAY);
     argsman.AddArg(
         "-datacarrier",
         strprintf("Relay and mine data carrier transactions (default: %d)",
                   DEFAULT_ACCEPT_DATACARRIER),
         ArgsManager::ALLOW_ANY, OptionsCategory::NODE_RELAY);
     argsman.AddArg(
         "-datacarriersize",
         strprintf("Maximum size of data in data carrier transactions "
                   "we relay and mine (default: %u)",
                   MAX_OP_RETURN_RELAY),
         ArgsManager::ALLOW_ANY, OptionsCategory::NODE_RELAY);
     argsman.AddArg(
         "-minrelaytxfee=<amt>",
         strprintf("Fees (in %s/kB) smaller than this are rejected for "
                   "relaying, mining and transaction creation (default: %s)",
                   ticker, FormatMoney(DEFAULT_MIN_RELAY_TX_FEE_PER_KB)),
         ArgsManager::ALLOW_ANY, OptionsCategory::NODE_RELAY);
     argsman.AddArg(
         "-whitelistrelay",
         strprintf("Add 'relay' permission to whitelisted inbound peers "
                   "with default permissions. This will accept relayed "
                   "transactions even when not relaying transactions "
                   "(default: %d)",
                   DEFAULT_WHITELISTRELAY),
         ArgsManager::ALLOW_ANY, OptionsCategory::NODE_RELAY);
     argsman.AddArg(
         "-whitelistforcerelay",
         strprintf("Add 'forcerelay' permission to whitelisted inbound peers"
                   " with default permissions. This will relay transactions "
                   "even if the transactions were already in the mempool "
                   "(default: %d)",
                   DEFAULT_WHITELISTFORCERELAY),
         ArgsManager::ALLOW_ANY, OptionsCategory::NODE_RELAY);
 
     // Not sure this really belongs here, but it will do for now.
     // FIXME: This doesn't work anyways.
     argsman.AddArg("-excessutxocharge=<amt>",
                    strprintf("Fees (in %s/kB) to charge per utxo created for "
                              "relaying, and mining (default: %s)",
                              ticker, FormatMoney(DEFAULT_UTXO_FEE)),
                    ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY,
                    OptionsCategory::NODE_RELAY);
 
     argsman.AddArg("-blockmaxsize=<n>",
                    strprintf("Set maximum block size in bytes (default: %d)",
                              DEFAULT_MAX_GENERATED_BLOCK_SIZE),
                    ArgsManager::ALLOW_ANY, OptionsCategory::BLOCK_CREATION);
     argsman.AddArg(
         "-blockmintxfee=<amt>",
         strprintf("Set lowest fee rate (in %s/kB) for transactions to "
                   "be included in block creation. (default: %s)",
                   ticker, FormatMoney(DEFAULT_BLOCK_MIN_TX_FEE_PER_KB)),
         ArgsManager::ALLOW_ANY, OptionsCategory::BLOCK_CREATION);
 
     argsman.AddArg("-blockversion=<n>",
                    "Override block version to test forking scenarios",
                    ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY,
                    OptionsCategory::BLOCK_CREATION);
 
     argsman.AddArg("-server", "Accept command line and JSON-RPC commands",
                    ArgsManager::ALLOW_ANY, OptionsCategory::RPC);
     argsman.AddArg("-rest",
                    strprintf("Accept public REST requests (default: %d)",
                              DEFAULT_REST_ENABLE),
                    ArgsManager::ALLOW_ANY, OptionsCategory::RPC);
     argsman.AddArg(
         "-rpcbind=<addr>[:port]",
         "Bind to given address to listen for JSON-RPC connections. Do not "
         "expose the RPC server to untrusted networks such as the public "
         "internet! This option is ignored unless -rpcallowip is also passed. "
         "Port is optional and overrides -rpcport.  Use [host]:port notation "
         "for IPv6. This option can be specified multiple times (default: "
         "127.0.0.1 and ::1 i.e., localhost)",
         ArgsManager::ALLOW_ANY | ArgsManager::NETWORK_ONLY |
             ArgsManager::SENSITIVE,
         OptionsCategory::RPC);
     argsman.AddArg(
         "-rpccookiefile=<loc>",
         "Location of the auth cookie. Relative paths will be prefixed "
         "by a net-specific datadir location. (default: data dir)",
         ArgsManager::ALLOW_ANY, OptionsCategory::RPC);
     argsman.AddArg("-rpcuser=<user>", "Username for JSON-RPC connections",
                    ArgsManager::ALLOW_ANY | ArgsManager::SENSITIVE,
                    OptionsCategory::RPC);
     argsman.AddArg("-rpcpassword=<pw>", "Password for JSON-RPC connections",
                    ArgsManager::ALLOW_ANY | ArgsManager::SENSITIVE,
                    OptionsCategory::RPC);
     argsman.AddArg(
         "-rpcwhitelist=<whitelist>",
         "Set a whitelist to filter incoming RPC calls for a specific user. The "
         "field <whitelist> comes in the format: <USERNAME>:<rpc 1>,<rpc "
         "2>,...,<rpc n>. If multiple whitelists are set for a given user, they "
         "are set-intersected. See -rpcwhitelistdefault documentation for "
         "information on default whitelist behavior.",
         ArgsManager::ALLOW_ANY, OptionsCategory::RPC);
     argsman.AddArg(
         "-rpcwhitelistdefault",
         "Sets default behavior for rpc whitelisting. Unless "
         "rpcwhitelistdefault is set to 0, if any -rpcwhitelist is set, the rpc "
         "server acts as if all rpc users are subject to "
         "empty-unless-otherwise-specified whitelists. If rpcwhitelistdefault "
         "is set to 1 and no -rpcwhitelist is set, rpc server acts as if all "
         "rpc users are subject to empty whitelists.",
         ArgsManager::ALLOW_BOOL, OptionsCategory::RPC);
     argsman.AddArg(
         "-rpcauth=<userpw>",
         "Username and HMAC-SHA-256 hashed password for JSON-RPC connections. "
         "The field <userpw> comes in the format: <USERNAME>:<SALT>$<HASH>. A "
         "canonical python script is included in share/rpcauth. The client then "
         "connects normally using the rpcuser=<USERNAME>/rpcpassword=<PASSWORD> "
         "pair of arguments. This option can be specified multiple times",
         ArgsManager::ALLOW_ANY | ArgsManager::SENSITIVE, OptionsCategory::RPC);
     argsman.AddArg("-rpcport=<port>",
                    strprintf("Listen for JSON-RPC connections on <port> "
                              "(default: %u, testnet: %u, regtest: %u)",
                              defaultBaseParams->RPCPort(),
                              testnetBaseParams->RPCPort(),
                              regtestBaseParams->RPCPort()),
                    ArgsManager::ALLOW_ANY | ArgsManager::NETWORK_ONLY,
                    OptionsCategory::RPC);
     argsman.AddArg(
         "-rpcallowip=<ip>",
         "Allow JSON-RPC connections from specified source. Valid for "
         "<ip> are a single IP (e.g. 1.2.3.4), a network/netmask (e.g. "
         "1.2.3.4/255.255.255.0) or a network/CIDR (e.g. 1.2.3.4/24). "
         "This option can be specified multiple times",
         ArgsManager::ALLOW_ANY, OptionsCategory::RPC);
     argsman.AddArg(
         "-rpcthreads=<n>",
         strprintf(
             "Set the number of threads to service RPC calls (default: %d)",
             DEFAULT_HTTP_THREADS),
         ArgsManager::ALLOW_ANY, OptionsCategory::RPC);
     argsman.AddArg(
         "-rpccorsdomain=value",
         "Domain from which to accept cross origin requests (browser enforced)",
         ArgsManager::ALLOW_ANY, OptionsCategory::RPC);
 
     argsman.AddArg("-rpcworkqueue=<n>",
                    strprintf("Set the depth of the work queue to service RPC "
                              "calls (default: %d)",
                              DEFAULT_HTTP_WORKQUEUE),
                    ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY,
                    OptionsCategory::RPC);
     argsman.AddArg("-rpcservertimeout=<n>",
                    strprintf("Timeout during HTTP requests (default: %d)",
                              DEFAULT_HTTP_SERVER_TIMEOUT),
                    ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY,
                    OptionsCategory::RPC);
 
 #if HAVE_DECL_DAEMON
     argsman.AddArg("-daemon",
                    "Run in the background as a daemon and accept commands",
                    ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
 #else
     hidden_args.emplace_back("-daemon");
 #endif
 
     // Avalanche options.
     argsman.AddArg(
         "-enableavalanche",
         strprintf("Enable avalanche (default: %u)", AVALANCHE_DEFAULT_ENABLED),
         ArgsManager::ALLOW_ANY, OptionsCategory::AVALANCHE);
     argsman.AddArg("-enableavalanchepeerdiscovery",
                    strprintf("Enable avalanche peer discovery (default: %u)",
                              AVALANCHE_DEFAULT_PEER_DISCOVERY_ENABLED),
                    ArgsManager::ALLOW_ANY, OptionsCategory::AVALANCHE);
     argsman.AddArg(
         "-avacooldown",
         strprintf("Mandatory cooldown between two avapoll (default: %u)",
                   AVALANCHE_DEFAULT_COOLDOWN),
         ArgsManager::ALLOW_ANY, OptionsCategory::AVALANCHE);
     argsman.AddArg(
         "-avadelegation",
         "Avalanche proof delegation to the master key used by this node "
         "(default: none). Should be used in conjunction with -avaproof and "
         "-avamasterkey",
         ArgsManager::ALLOW_ANY, OptionsCategory::AVALANCHE);
     argsman.AddArg("-avaproof",
                    "Avalanche proof to be used by this node (default: none)",
                    ArgsManager::ALLOW_ANY, OptionsCategory::AVALANCHE);
     argsman.AddArg(
         "-legacyavaproof",
         strprintf("Use the legacy avalanche proof format (default: %u)",
                   AVALANCHE_DEFAULT_LEGACY_PROOF),
         ArgsManager::ALLOW_BOOL, OptionsCategory::AVALANCHE);
     argsman.AddArg("-avamasterkey",
                    "Master key associated with the proof. If a proof is "
                    "required, this is mandatory.",
                    ArgsManager::ALLOW_ANY, OptionsCategory::AVALANCHE);
     argsman.AddArg("-avasessionkey", "Avalanche session key (default: random)",
                    ArgsManager::ALLOW_ANY, OptionsCategory::AVALANCHE);
 
     // Add the hidden options
     argsman.AddHiddenArgs(hidden_args);
 }
 
 std::string LicenseInfo() {
     const std::string URL_SOURCE_CODE =
         "<https://github.com/Bitcoin-ABC/bitcoin-abc>";
     const std::string URL_WEBSITE = "<https://www.bitcoinabc.org>";
 
     return CopyrightHolders(strprintf(_("Copyright (C) %i-%i").translated, 2009,
                                       COPYRIGHT_YEAR) +
                             " ") +
            "\n" + "\n" +
            strprintf(_("Please contribute if you find %s useful. "
                        "Visit %s for further information about the software.")
                          .translated,
                      PACKAGE_NAME, URL_WEBSITE) +
            "\n" +
            strprintf(_("The source code is available from %s.").translated,
                      URL_SOURCE_CODE) +
            "\n" + "\n" + _("This is experimental software.").translated + "\n" +
            strprintf(_("Distributed under the MIT software license, see the "
                        "accompanying file %s or %s")
                          .translated,
                      "COPYING", "<https://opensource.org/licenses/MIT>") +
            "\n" + "\n" +
            strprintf(_("This product includes software developed by the "
                        "OpenSSL Project for use in the OpenSSL Toolkit %s and "
                        "cryptographic software written by Eric Young and UPnP "
                        "software written by Thomas Bernard.")
                          .translated,
                      "<https://www.openssl.org>") +
            "\n";
 }
 
 static bool fHaveGenesis = false;
 static Mutex g_genesis_wait_mutex;
 static std::condition_variable g_genesis_wait_cv;
 
 static void BlockNotifyGenesisWait(const CBlockIndex *pBlockIndex) {
     if (pBlockIndex != nullptr) {
         {
             LOCK(g_genesis_wait_mutex);
             fHaveGenesis = true;
         }
         g_genesis_wait_cv.notify_all();
     }
 }
 
 struct CImportingNow {
     CImportingNow() {
         assert(fImporting == false);
         fImporting = true;
     }
 
     ~CImportingNow() {
         assert(fImporting == true);
         fImporting = false;
     }
 };
 
 // If we're using -prune with -reindex, then delete block files that will be
 // ignored by the reindex.  Since reindexing works by starting at block file 0
 // and looping until a blockfile is missing, do the same here to delete any
 // later block files after a gap. Also delete all rev files since they'll be
 // rewritten by the reindex anyway. This ensures that vinfoBlockFile is in sync
 // with what's actually on disk by the time we start downloading, so that
 // pruning works correctly.
 static void CleanupBlockRevFiles() {
     std::map<std::string, fs::path> mapBlockFiles;
 
     // Glob all blk?????.dat and rev?????.dat files from the blocks directory.
     // Remove the rev files immediately and insert the blk file paths into an
     // ordered map keyed by block file index.
     LogPrintf("Removing unusable blk?????.dat and rev?????.dat files for "
               "-reindex with -prune\n");
     const auto directoryIterator = fs::directory_iterator{GetBlocksDir()};
     for (const auto &file : directoryIterator) {
         const auto fileName = file.path().filename().string();
         if (fs::is_regular_file(file) && fileName.length() == 12 &&
             fileName.substr(8, 4) == ".dat") {
             if (fileName.substr(0, 3) == "blk") {
                 mapBlockFiles[fileName.substr(3, 5)] = file.path();
             } else if (fileName.substr(0, 3) == "rev") {
                 remove(file.path());
             }
         }
     }
 
     // Remove all block files that aren't part of a contiguous set starting at
     // zero by walking the ordered map (keys are block file indices) by keeping
     // a separate counter. Once we hit a gap (or if 0 doesn't exist) start
     // removing block files.
     int contiguousCounter = 0;
     for (const auto &item : mapBlockFiles) {
         if (atoi(item.first) == contiguousCounter) {
             contiguousCounter++;
             continue;
         }
         remove(item.second);
     }
 }
 
 static void ThreadImport(const Config &config, ChainstateManager &chainman,
                          std::vector<fs::path> vImportFiles,
                          const ArgsManager &args) {
     ScheduleBatchPriority();
 
     {
         const CChainParams &chainParams = config.GetChainParams();
 
         CImportingNow imp;
 
         // -reindex
         if (fReindex) {
             int nFile = 0;
             while (true) {
                 FlatFilePos pos(nFile, 0);
                 if (!fs::exists(GetBlockPosFilename(pos))) {
                     // No block files left to reindex
                     break;
                 }
                 FILE *file = OpenBlockFile(pos, true);
                 if (!file) {
                     // This error is logged in OpenBlockFile
                     break;
                 }
                 LogPrintf("Reindexing block file blk%05u.dat...\n",
                           (unsigned int)nFile);
                 LoadExternalBlockFile(config, file, &pos);
                 if (ShutdownRequested()) {
                     LogPrintf("Shutdown requested. Exit %s\n", __func__);
                     return;
                 }
                 nFile++;
             }
             pblocktree->WriteReindexing(false);
             fReindex = false;
             LogPrintf("Reindexing finished\n");
             // To avoid ending up in a situation without genesis block, re-try
             // initializing (no-op if reindexing worked):
             LoadGenesisBlock(chainParams);
         }
 
         // -loadblock=
         for (const fs::path &path : vImportFiles) {
             FILE *file = fsbridge::fopen(path, "rb");
             if (file) {
                 LogPrintf("Importing blocks file %s...\n", path.string());
                 LoadExternalBlockFile(config, file);
                 if (ShutdownRequested()) {
                     LogPrintf("Shutdown requested. Exit %s\n", __func__);
                     return;
                 }
             } else {
                 LogPrintf("Warning: Could not open blocks file %s\n",
                           path.string());
             }
         }
 
         // Reconsider blocks we know are valid. They may have been marked
         // invalid by, for instance, running an outdated version of the node
         // software.
         const MapCheckpoints &checkpoints =
             chainParams.Checkpoints().mapCheckpoints;
         for (const MapCheckpoints::value_type &i : checkpoints) {
             const BlockHash &hash = i.second;
 
             LOCK(cs_main);
             CBlockIndex *pblockindex = LookupBlockIndex(hash);
             if (pblockindex && !pblockindex->nStatus.isValid()) {
                 LogPrintf("Reconsidering checkpointed block %s ...\n",
                           hash.GetHex());
                 ResetBlockFailureFlags(pblockindex);
             }
         }
 
         // scan for better chains in the block chain database, that are not yet
         // connected in the active best chain
 
         // We can't hold cs_main during ActivateBestChain even though we're
         // accessing the chainman unique_ptrs since ABC requires us not to be
         // holding cs_main, so retrieve the relevant pointers before the ABC
         // call.
         for (CChainState *chainstate :
              WITH_LOCK(::cs_main, return chainman.GetAll())) {
             BlockValidationState state;
             if (!chainstate->ActivateBestChain(config, state, nullptr)) {
                 LogPrintf("Failed to connect best block (%s)\n",
                           state.ToString());
                 StartShutdown();
                 return;
             }
         }
 
         if (args.GetBoolArg("-stopafterblockimport",
                             DEFAULT_STOPAFTERBLOCKIMPORT)) {
             LogPrintf("Stopping after block import\n");
             StartShutdown();
             return;
         }
     } // End scope of CImportingNow
     chainman.ActiveChainstate().LoadMempool(config, args);
 }
 
 /** Sanity checks
  *  Ensure that Bitcoin is running in a usable environment with all
  *  necessary library support.
  */
 static bool InitSanityCheck() {
     if (!ECC_InitSanityCheck()) {
         return InitError(Untranslated(
             "Elliptic curve cryptography sanity check failure. Aborting."));
     }
 
     if (!glibcxx_sanity_test()) {
         return false;
     }
 
     if (!Random_SanityCheck()) {
         return InitError(Untranslated(
             "OS cryptographic RNG sanity check failure. Aborting."));
     }
 
     return true;
 }
 
 static bool AppInitServers(Config &config,
                            HTTPRPCRequestProcessor &httpRPCRequestProcessor,
                            NodeContext &node) {
     const ArgsManager &args = *Assert(node.args);
     RPCServerSignals::OnStarted(&OnRPCStarted);
     RPCServerSignals::OnStopped(&OnRPCStopped);
     if (!InitHTTPServer(config)) {
         return false;
     }
 
     StartRPC();
     node.rpc_interruption_point = RpcInterruptionPoint;
 
     if (!StartHTTPRPC(httpRPCRequestProcessor)) {
         return false;
     }
     if (args.GetBoolArg("-rest", DEFAULT_REST_ENABLE)) {
         StartREST(httpRPCRequestProcessor.context);
     }
 
     StartHTTPServer();
     return true;
 }
 
 // Parameter interaction based on rules
 void InitParameterInteraction(ArgsManager &args) {
     // when specifying an explicit binding address, you want to listen on it
     // even when -connect or -proxy is specified.
     if (args.IsArgSet("-bind")) {
         if (args.SoftSetBoolArg("-listen", true)) {
             LogPrintf(
                 "%s: parameter interaction: -bind set -> setting -listen=1\n",
                 __func__);
         }
     }
     if (args.IsArgSet("-whitebind")) {
         if (args.SoftSetBoolArg("-listen", true)) {
             LogPrintf("%s: parameter interaction: -whitebind set -> setting "
                       "-listen=1\n",
                       __func__);
         }
     }
 
     if (args.IsArgSet("-connect")) {
         // when only connecting to trusted nodes, do not seed via DNS, or listen
         // by default.
         if (args.SoftSetBoolArg("-dnsseed", false)) {
             LogPrintf("%s: parameter interaction: -connect set -> setting "
                       "-dnsseed=0\n",
                       __func__);
         }
         if (args.SoftSetBoolArg("-listen", false)) {
             LogPrintf("%s: parameter interaction: -connect set -> setting "
                       "-listen=0\n",
                       __func__);
         }
     }
 
     if (args.IsArgSet("-proxy")) {
         // to protect privacy, do not listen by default if a default proxy
         // server is specified.
         if (args.SoftSetBoolArg("-listen", false)) {
             LogPrintf(
                 "%s: parameter interaction: -proxy set -> setting -listen=0\n",
                 __func__);
         }
         // to protect privacy, do not use UPNP when a proxy is set. The user may
         // still specify -listen=1 to listen locally, so don't rely on this
         // happening through -listen below.
         if (args.SoftSetBoolArg("-upnp", false)) {
             LogPrintf(
                 "%s: parameter interaction: -proxy set -> setting -upnp=0\n",
                 __func__);
         }
         // to protect privacy, do not discover addresses by default
         if (args.SoftSetBoolArg("-discover", false)) {
             LogPrintf("%s: parameter interaction: -proxy set -> setting "
                       "-discover=0\n",
                       __func__);
         }
     }
 
     if (!args.GetBoolArg("-listen", DEFAULT_LISTEN)) {
         // do not map ports or try to retrieve public IP when not listening
         // (pointless)
         if (args.SoftSetBoolArg("-upnp", false)) {
             LogPrintf(
                 "%s: parameter interaction: -listen=0 -> setting -upnp=0\n",
                 __func__);
         }
         if (args.SoftSetBoolArg("-discover", false)) {
             LogPrintf(
                 "%s: parameter interaction: -listen=0 -> setting -discover=0\n",
                 __func__);
         }
         if (args.SoftSetBoolArg("-listenonion", false)) {
             LogPrintf("%s: parameter interaction: -listen=0 -> setting "
                       "-listenonion=0\n",
                       __func__);
         }
     }
 
     if (args.IsArgSet("-externalip")) {
         // if an explicit public IP is specified, do not try to find others
         if (args.SoftSetBoolArg("-discover", false)) {
             LogPrintf("%s: parameter interaction: -externalip set -> setting "
                       "-discover=0\n",
                       __func__);
         }
     }
 
     // disable whitelistrelay in blocksonly mode
     if (args.GetBoolArg("-blocksonly", DEFAULT_BLOCKSONLY)) {
         if (args.SoftSetBoolArg("-whitelistrelay", false)) {
             LogPrintf("%s: parameter interaction: -blocksonly=1 -> setting "
                       "-whitelistrelay=0\n",
                       __func__);
         }
     }
 
     // Forcing relay from whitelisted hosts implies we will accept relays from
     // them in the first place.
     if (args.GetBoolArg("-whitelistforcerelay", DEFAULT_WHITELISTFORCERELAY)) {
         if (args.SoftSetBoolArg("-whitelistrelay", true)) {
             LogPrintf("%s: parameter interaction: -whitelistforcerelay=1 -> "
                       "setting -whitelistrelay=1\n",
                       __func__);
         }
     }
 }
 
 /**
  * Initialize global loggers.
  *
  * Note that this is called very early in the process lifetime, so you should be
  * careful about what global state you rely on here.
  */
 void InitLogging(const ArgsManager &args) {
     LogInstance().m_print_to_file = !args.IsArgNegated("-debuglogfile");
     LogInstance().m_file_path =
         AbsPathForConfigVal(args.GetArg("-debuglogfile", DEFAULT_DEBUGLOGFILE));
 
     LogInstance().m_print_to_console =
         args.GetBoolArg("-printtoconsole", !args.GetBoolArg("-daemon", false));
     LogInstance().m_log_timestamps =
         args.GetBoolArg("-logtimestamps", DEFAULT_LOGTIMESTAMPS);
     LogInstance().m_log_time_micros =
         args.GetBoolArg("-logtimemicros", DEFAULT_LOGTIMEMICROS);
 #ifdef HAVE_THREAD_LOCAL
     LogInstance().m_log_threadnames =
         args.GetBoolArg("-logthreadnames", DEFAULT_LOGTHREADNAMES);
 #endif
 
     fLogIPs = args.GetBoolArg("-logips", DEFAULT_LOGIPS);
 
     std::string version_string = FormatFullVersion();
 #ifdef DEBUG
     version_string += " (debug build)";
 #else
     version_string += " (release build)";
 #endif
     LogPrintf("%s version %s\n", CLIENT_NAME, version_string);
 }
 
 namespace { // Variables internal to initialization process only
 
 int nMaxConnections;
 int nUserMaxConnections;
 int nFD;
 ServiceFlags nLocalServices = ServiceFlags(NODE_NETWORK | NODE_NETWORK_LIMITED);
 int64_t peer_connect_timeout;
 std::set<BlockFilterType> g_enabled_filter_types;
 
 } // namespace
 
 [[noreturn]] static void new_handler_terminate() {
     // Rather than throwing std::bad-alloc if allocation fails, terminate
     // immediately to (try to) avoid chain corruption. Since LogPrintf may
     // itself allocate memory, set the handler directly to terminate first.
     std::set_new_handler(std::terminate);
     LogPrintf("Error: Out of memory. Terminating.\n");
 
     // The log was successful, terminate now.
     std::terminate();
 };
 
 bool AppInitBasicSetup(ArgsManager &args) {
 // Step 1: setup
 #ifdef _MSC_VER
     // Turn off Microsoft heap dump noise
     _CrtSetReportMode(_CRT_WARN, _CRTDBG_MODE_FILE);
     _CrtSetReportFile(_CRT_WARN, CreateFileA("NUL", GENERIC_WRITE, 0, nullptr,
                                              OPEN_EXISTING, 0, 0));
     // Disable confusing "helpful" text message on abort, Ctrl-C
     _set_abort_behavior(0, _WRITE_ABORT_MSG | _CALL_REPORTFAULT);
 #endif
 #ifdef WIN32
     // Enable Data Execution Prevention (DEP)
     SetProcessDEPPolicy(PROCESS_DEP_ENABLE);
 #endif
 
     if (!SetupNetworking()) {
         return InitError(Untranslated("Initializing networking failed"));
     }
 
 #ifndef WIN32
     if (!args.GetBoolArg("-sysperms", false)) {
         umask(077);
     }
 
     // Clean shutdown on SIGTERM
     registerSignalHandler(SIGTERM, HandleSIGTERM);
     registerSignalHandler(SIGINT, HandleSIGTERM);
 
     // Reopen debug.log on SIGHUP
     registerSignalHandler(SIGHUP, HandleSIGHUP);
 
     // Ignore SIGPIPE, otherwise it will bring the daemon down if the client
     // closes unexpectedly
     signal(SIGPIPE, SIG_IGN);
 #else
     SetConsoleCtrlHandler(consoleCtrlHandler, true);
 #endif
 
     std::set_new_handler(new_handler_terminate);
 
     return true;
 }
 
 bool AppInitParameterInteraction(Config &config, const ArgsManager &args) {
     const CChainParams &chainparams = config.GetChainParams();
     // Step 2: parameter interactions
 
     // also see: InitParameterInteraction()
 
     // Error if network-specific options (-addnode, -connect, etc) are
     // specified in default section of config file, but not overridden
     // on the command line or in this network's section of the config file.
     std::string network = args.GetChainName();
     bilingual_str errors;
     for (const auto &arg : args.GetUnsuitableSectionOnlyArgs()) {
         errors += strprintf(_("Config setting for %s only applied on %s "
                               "network when in [%s] section.") +
                                 Untranslated("\n"),
                             arg, network, network);
     }
 
     if (!errors.empty()) {
         return InitError(errors);
     }
 
     // Warn if unrecognized section name are present in the config file.
     bilingual_str warnings;
     for (const auto &section : args.GetUnrecognizedSections()) {
         warnings += strprintf(Untranslated("%s:%i ") +
                                   _("Section [%s] is not recognized.") +
                                   Untranslated("\n"),
                               section.m_file, section.m_line, section.m_name);
     }
 
     if (!warnings.empty()) {
         InitWarning(warnings);
     }
 
     if (!fs::is_directory(GetBlocksDir())) {
         return InitError(
             strprintf(_("Specified blocks directory \"%s\" does not exist."),
                       args.GetArg("-blocksdir", "")));
     }
 
     // parse and validate enabled filter types
     std::string blockfilterindex_value =
         args.GetArg("-blockfilterindex", DEFAULT_BLOCKFILTERINDEX);
     if (blockfilterindex_value == "" || blockfilterindex_value == "1") {
         g_enabled_filter_types = AllBlockFilterTypes();
     } else if (blockfilterindex_value != "0") {
         const std::vector<std::string> names =
             args.GetArgs("-blockfilterindex");
         for (const auto &name : names) {
             BlockFilterType filter_type;
             if (!BlockFilterTypeByName(name, filter_type)) {
                 return InitError(
                     strprintf(_("Unknown -blockfilterindex value %s."), name));
             }
             g_enabled_filter_types.insert(filter_type);
         }
     }
 
     // Signal NODE_COMPACT_FILTERS if peerblockfilters and basic filters index
     // are both enabled.
     if (gArgs.GetBoolArg("-peerblockfilters", DEFAULT_PEERBLOCKFILTERS)) {
         if (g_enabled_filter_types.count(BlockFilterType::BASIC) != 1) {
             return InitError(
                 _("Cannot set -peerblockfilters without -blockfilterindex."));
         }
 
         nLocalServices = ServiceFlags(nLocalServices | NODE_COMPACT_FILTERS);
     }
 
     // if using block pruning, then disallow txindex
     if (args.GetArg("-prune", 0)) {
         if (args.GetBoolArg("-txindex", DEFAULT_TXINDEX)) {
             return InitError(_("Prune mode is incompatible with -txindex."));
         }
         if (!g_enabled_filter_types.empty()) {
             return InitError(
                 _("Prune mode is incompatible with -blockfilterindex."));
         }
     }
 
     // -bind and -whitebind can't be set when not listening
     size_t nUserBind =
         args.GetArgs("-bind").size() + args.GetArgs("-whitebind").size();
     if (nUserBind != 0 && !args.GetBoolArg("-listen", DEFAULT_LISTEN)) {
         return InitError(Untranslated(
             "Cannot set -bind or -whitebind together with -listen=0"));
     }
 
     // Make sure enough file descriptors are available
     int nBind = std::max(nUserBind, size_t(1));
     nUserMaxConnections =
         args.GetArg("-maxconnections", DEFAULT_MAX_PEER_CONNECTIONS);
     nMaxConnections = std::max(nUserMaxConnections, 0);
 
     // Trim requested connection counts, to fit into system limitations
     // <int> in std::min<int>(...) to work around FreeBSD compilation issue
     // described in #2695
     nFD = RaiseFileDescriptorLimit(nMaxConnections + nBind +
                                    MIN_CORE_FILEDESCRIPTORS +
                                    MAX_ADDNODE_CONNECTIONS);
 #ifdef USE_POLL
     int fd_max = nFD;
 #else
     int fd_max = FD_SETSIZE;
 #endif
     nMaxConnections =
         std::max(std::min<int>(nMaxConnections, fd_max - nBind -
                                                     MIN_CORE_FILEDESCRIPTORS -
                                                     MAX_ADDNODE_CONNECTIONS),
                  0);
     if (nFD < MIN_CORE_FILEDESCRIPTORS) {
         return InitError(_("Not enough file descriptors available."));
     }
     nMaxConnections =
         std::min(nFD - MIN_CORE_FILEDESCRIPTORS - MAX_ADDNODE_CONNECTIONS,
                  nMaxConnections);
 
     if (nMaxConnections < nUserMaxConnections) {
         // Not categorizing as "Warning" because this is the normal behavior for
         // platforms using the select() interface for which FD_SETSIZE is
         // usually 1024.
         LogPrintf("Reducing -maxconnections from %d to %d, because of system "
                   "limitations.\n",
                   nUserMaxConnections, nMaxConnections);
     }
 
     // Step 3: parameter-to-internal-flags
     if (args.IsArgSet("-debug")) {
         // Special-case: if -debug=0/-nodebug is set, turn off debugging
         // messages
         const std::vector<std::string> &categories = args.GetArgs("-debug");
         if (std::none_of(
                 categories.begin(), categories.end(),
                 [](std::string cat) { return cat == "0" || cat == "none"; })) {
             for (const auto &cat : categories) {
                 if (!LogInstance().EnableCategory(cat)) {
                     InitWarning(
                         strprintf(_("Unsupported logging category %s=%s."),
                                   "-debug", cat));
                 }
             }
         }
     }
 
     // Now remove the logging categories which were explicitly excluded
     for (const std::string &cat : args.GetArgs("-debugexclude")) {
         if (!LogInstance().DisableCategory(cat)) {
             InitWarning(strprintf(_("Unsupported logging category %s=%s."),
                                   "-debugexclude", cat));
         }
     }
 
     fCheckBlockIndex = args.GetBoolArg("-checkblockindex",
                                        chainparams.DefaultConsistencyChecks());
     fCheckpointsEnabled =
         args.GetBoolArg("-checkpoints", DEFAULT_CHECKPOINTS_ENABLED);
     if (fCheckpointsEnabled) {
         LogPrintf("Checkpoints will be verified.\n");
     } else {
         LogPrintf("Skipping checkpoint verification.\n");
     }
 
     hashAssumeValid = BlockHash::fromHex(
         args.GetArg("-assumevalid",
                     chainparams.GetConsensus().defaultAssumeValid.GetHex()));
     if (!hashAssumeValid.IsNull()) {
         LogPrintf("Assuming ancestors of block %s have valid signatures.\n",
                   hashAssumeValid.GetHex());
     } else {
         LogPrintf("Validating signatures for all blocks.\n");
     }
 
     if (args.IsArgSet("-minimumchainwork")) {
         const std::string minChainWorkStr =
             args.GetArg("-minimumchainwork", "");
         if (!IsHexNumber(minChainWorkStr)) {
             return InitError(strprintf(
                 Untranslated(
                     "Invalid non-hex (%s) minimum chain work value specified"),
                 minChainWorkStr));
         }
         nMinimumChainWork = UintToArith256(uint256S(minChainWorkStr));
     } else {
         nMinimumChainWork =
             UintToArith256(chainparams.GetConsensus().nMinimumChainWork);
     }
     LogPrintf("Setting nMinimumChainWork=%s\n", nMinimumChainWork.GetHex());
     if (nMinimumChainWork <
         UintToArith256(chainparams.GetConsensus().nMinimumChainWork)) {
         LogPrintf("Warning: nMinimumChainWork set below default value of %s\n",
                   chainparams.GetConsensus().nMinimumChainWork.GetHex());
     }
 
     // mempool limits
     int64_t nMempoolSizeMax =
         args.GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000;
     int64_t nMempoolSizeMin =
         args.GetArg("-limitdescendantsize", DEFAULT_DESCENDANT_SIZE_LIMIT) *
         1000 * 40;
     if (nMempoolSizeMax < 0 || nMempoolSizeMax < nMempoolSizeMin) {
         return InitError(strprintf(_("-maxmempool must be at least %d MB"),
                                    std::ceil(nMempoolSizeMin / 1000000.0)));
     }
 
     // Configure excessive block size.
     const int64_t nProposedExcessiveBlockSize =
         args.GetArg("-excessiveblocksize", DEFAULT_MAX_BLOCK_SIZE);
     if (nProposedExcessiveBlockSize <= 0 ||
         !config.SetMaxBlockSize(nProposedExcessiveBlockSize)) {
         return InitError(
             _("Excessive block size must be > 1,000,000 bytes (1MB)"));
     }
 
     // Check blockmaxsize does not exceed maximum accepted block size.
     const int64_t nProposedMaxGeneratedBlockSize =
         args.GetArg("-blockmaxsize", DEFAULT_MAX_GENERATED_BLOCK_SIZE);
     if (nProposedMaxGeneratedBlockSize <= 0) {
         return InitError(_("Max generated block size must be greater than 0"));
     }
     if (uint64_t(nProposedMaxGeneratedBlockSize) > config.GetMaxBlockSize()) {
         return InitError(_("Max generated block size (blockmaxsize) cannot "
                            "exceed the excessive block size "
                            "(excessiveblocksize)"));
     }
 
     // block pruning; get the amount of disk space (in MiB) to allot for block &
     // undo files
     int64_t nPruneArg = args.GetArg("-prune", 0);
     if (nPruneArg < 0) {
         return InitError(
             _("Prune cannot be configured with a negative value."));
     }
     nPruneTarget = (uint64_t)nPruneArg * 1024 * 1024;
     if (nPruneArg == 1) {
         // manual pruning: -prune=1
         LogPrintf("Block pruning enabled.  Use RPC call "
                   "pruneblockchain(height) to manually prune block and undo "
                   "files.\n");
         nPruneTarget = std::numeric_limits<uint64_t>::max();
         fPruneMode = true;
     } else if (nPruneTarget) {
         if (nPruneTarget < MIN_DISK_SPACE_FOR_BLOCK_FILES) {
             return InitError(
                 strprintf(_("Prune configured below the minimum of %d MiB. "
                             "Please use a higher number."),
                           MIN_DISK_SPACE_FOR_BLOCK_FILES / 1024 / 1024));
         }
         LogPrintf("Prune configured to target %u MiB on disk for block and "
                   "undo files.\n",
                   nPruneTarget / 1024 / 1024);
         fPruneMode = true;
     }
 
     nConnectTimeout = args.GetArg("-timeout", DEFAULT_CONNECT_TIMEOUT);
     if (nConnectTimeout <= 0) {
         nConnectTimeout = DEFAULT_CONNECT_TIMEOUT;
     }
 
     peer_connect_timeout =
         args.GetArg("-peertimeout", DEFAULT_PEER_CONNECT_TIMEOUT);
     if (peer_connect_timeout <= 0) {
         return InitError(Untranslated(
             "peertimeout cannot be configured with a negative value."));
     }
 
     // Obtain the amount to charge excess UTXO
     if (args.IsArgSet("-excessutxocharge")) {
         Amount n = Amount::zero();
         auto parsed = ParseMoney(args.GetArg("-excessutxocharge", ""), n);
         if (!parsed || Amount::zero() > n) {
             return InitError(AmountErrMsg(
                 "excessutxocharge", args.GetArg("-excessutxocharge", "")));
         }
         config.SetExcessUTXOCharge(n);
     } else {
         config.SetExcessUTXOCharge(DEFAULT_UTXO_FEE);
     }
 
     if (args.IsArgSet("-minrelaytxfee")) {
         Amount n = Amount::zero();
         auto parsed = ParseMoney(args.GetArg("-minrelaytxfee", ""), n);
         if (!parsed || n == Amount::zero()) {
             return InitError(AmountErrMsg("minrelaytxfee",
                                           args.GetArg("-minrelaytxfee", "")));
         }
         // High fee check is done afterward in CWallet::CreateWalletFromFile()
         ::minRelayTxFee = CFeeRate(n);
     }
 
     // Sanity check argument for min fee for including tx in block
     // TODO: Harmonize which arguments need sanity checking and where that
     // happens.
     if (args.IsArgSet("-blockmintxfee")) {
         Amount n = Amount::zero();
         if (!ParseMoney(args.GetArg("-blockmintxfee", ""), n)) {
             return InitError(AmountErrMsg("blockmintxfee",
                                           args.GetArg("-blockmintxfee", "")));
         }
     }
 
     // Feerate used to define dust.  Shouldn't be changed lightly as old
     // implementations may inadvertently create non-standard transactions.
     if (args.IsArgSet("-dustrelayfee")) {
         Amount n = Amount::zero();
         auto parsed = ParseMoney(args.GetArg("-dustrelayfee", ""), n);
         if (!parsed || Amount::zero() == n) {
             return InitError(
                 AmountErrMsg("dustrelayfee", args.GetArg("-dustrelayfee", "")));
         }
         dustRelayFee = CFeeRate(n);
     }
 
     fRequireStandard =
         !args.GetBoolArg("-acceptnonstdtxn", !chainparams.RequireStandard());
     if (!chainparams.IsTestChain() && !fRequireStandard) {
         return InitError(strprintf(
             Untranslated(
                 "acceptnonstdtxn is not currently supported for %s chain"),
             chainparams.NetworkIDString()));
     }
     nBytesPerSigOp = args.GetArg("-bytespersigop", nBytesPerSigOp);
 
     if (!g_wallet_init_interface.ParameterInteraction()) {
         return false;
     }
 
     fIsBareMultisigStd =
         args.GetBoolArg("-permitbaremultisig", DEFAULT_PERMIT_BAREMULTISIG);
     fAcceptDatacarrier =
         args.GetBoolArg("-datacarrier", DEFAULT_ACCEPT_DATACARRIER);
 
     // Option to startup with mocktime set (used for regression testing):
     SetMockTime(args.GetArg("-mocktime", 0)); // SetMockTime(0) is a no-op
 
     if (args.GetBoolArg("-peerbloomfilters", DEFAULT_PEERBLOOMFILTERS)) {
         nLocalServices = ServiceFlags(nLocalServices | NODE_BLOOM);
     }
 
     nMaxTipAge = args.GetArg("-maxtipage", DEFAULT_MAX_TIP_AGE);
 
     return true;
 }
 
 static bool LockDataDirectory(bool probeOnly) {
     // Make sure only a single Bitcoin process is using the data directory.
     fs::path datadir = GetDataDir();
     if (!DirIsWritable(datadir)) {
         return InitError(strprintf(
             _("Cannot write to data directory '%s'; check permissions."),
             datadir.string()));
     }
     if (!LockDirectory(datadir, ".lock", probeOnly)) {
         return InitError(strprintf(_("Cannot obtain a lock on data directory "
                                      "%s. %s is probably already running."),
                                    datadir.string(), PACKAGE_NAME));
     }
     return true;
 }
 
 bool AppInitSanityChecks() {
     // Step 4: sanity checks
 
     // Initialize elliptic curve code
     std::string sha256_algo = SHA256AutoDetect();
     LogPrintf("Using the '%s' SHA256 implementation\n", sha256_algo);
     RandomInit();
     ECC_Start();
     globalVerifyHandle.reset(new ECCVerifyHandle());
 
     // Sanity check
     if (!InitSanityCheck()) {
         return InitError(strprintf(
             _("Initialization sanity check failed. %s is shutting down."),
             PACKAGE_NAME));
     }
 
     // Probe the data directory lock to give an early error message, if possible
     // We cannot hold the data directory lock here, as the forking for daemon()
     // hasn't yet happened, and a fork will cause weird behavior to it.
     return LockDataDirectory(true);
 }
 
 bool AppInitLockDataDirectory() {
     // After daemonization get the data directory lock again and hold on to it
     // until exit. This creates a slight window for a race condition to happen,
     // however this condition is harmless: it will at most make us exit without
     // printing a message to console.
     if (!LockDataDirectory(false)) {
         // Detailed error printed inside LockDataDirectory
         return false;
     }
     return true;
 }
 
 bool AppInitInterfaces(NodeContext &node) {
     node.chain = interfaces::MakeChain(node, Params());
     // Create client interfaces for wallets that are supposed to be loaded
     // according to -wallet and -disablewallet options. This only constructs
     // the interfaces, it doesn't load wallet data. Wallets actually get loaded
     // when load() and start() interface methods are called below.
     g_wallet_init_interface.Construct(node);
     return true;
 }
 
 bool AppInitMain(Config &config, RPCServer &rpcServer,
                  HTTPRPCRequestProcessor &httpRPCRequestProcessor,
                  NodeContext &node,
                  interfaces::BlockAndHeaderTipInfo *tip_info) {
     // Step 4a: application initialization
     const ArgsManager &args = *Assert(node.args);
     const CChainParams &chainparams = config.GetChainParams();
 
     if (!CreatePidFile(args)) {
         // Detailed error printed inside CreatePidFile().
         return false;
     }
 
     BCLog::Logger &logger = LogInstance();
     if (logger.m_print_to_file) {
         if (args.GetBoolArg("-shrinkdebugfile",
                             logger.DefaultShrinkDebugFile())) {
             // Do this first since it both loads a bunch of debug.log into
             // memory, and because this needs to happen before any other
             // debug.log printing.
             logger.ShrinkDebugFile();
         }
     }
 
     if (!logger.StartLogging()) {
         return InitError(
             strprintf(Untranslated("Could not open debug log file %s"),
                       logger.m_file_path.string()));
     }
 
     if (!logger.m_log_timestamps) {
         LogPrintf("Startup time: %s\n", FormatISO8601DateTime(GetTime()));
     }
     LogPrintf("Default data directory %s\n", GetDefaultDataDir().string());
     LogPrintf("Using data directory %s\n", GetDataDir().string());
 
     // Only log conf file usage message if conf file actually exists.
     fs::path config_file_path =
         GetConfigFile(args.GetArg("-conf", BITCOIN_CONF_FILENAME));
     if (fs::exists(config_file_path)) {
         LogPrintf("Config file: %s\n", config_file_path.string());
     } else if (args.IsArgSet("-conf")) {
         // Warn if no conf file exists at path provided by user
         InitWarning(
             strprintf(_("The specified config file %s does not exist\n"),
                       config_file_path.string()));
     } else {
         // Not categorizing as "Warning" because it's the default behavior
         LogPrintf("Config file: %s (not found, skipping)\n",
                   config_file_path.string());
     }
 
     // Log the config arguments to debug.log
     args.LogArgs();
 
     LogPrintf("Using at most %i automatic connections (%i file descriptors "
               "available)\n",
               nMaxConnections, nFD);
 
     // Warn about relative -datadir path.
     if (args.IsArgSet("-datadir") &&
         !fs::path(args.GetArg("-datadir", "")).is_absolute()) {
         LogPrintf("Warning: relative datadir option '%s' specified, which will "
                   "be interpreted relative to the current working directory "
                   "'%s'. This is fragile, because if bitcoin is started in the "
                   "future from a different location, it will be unable to "
                   "locate the current data files. There could also be data "
                   "loss if bitcoin is started while in a temporary "
                   "directory.\n",
                   args.GetArg("-datadir", ""), fs::current_path().string());
     }
 
     InitSignatureCache();
     InitScriptExecutionCache();
 
     int script_threads = args.GetArg("-par", DEFAULT_SCRIPTCHECK_THREADS);
     if (script_threads <= 0) {
         // -par=0 means autodetect (number of cores - 1 script threads)
         // -par=-n means "leave n cores free" (number of cores - n - 1 script
         // threads)
         script_threads += GetNumCores();
     }
 
     // Subtract 1 because the main thread counts towards the par threads
     script_threads = std::max(script_threads - 1, 0);
 
     // Number of script-checking threads <= MAX_SCRIPTCHECK_THREADS
     script_threads = std::min(script_threads, MAX_SCRIPTCHECK_THREADS);
 
     LogPrintf("Script verification uses %d additional threads\n",
               script_threads);
     if (script_threads >= 1) {
         for (int i = 0; i < script_threads; ++i) {
             threadGroup.create_thread([i]() { return ThreadScriptCheck(i); });
         }
     }
 
     assert(!node.scheduler);
     node.scheduler = std::make_unique<CScheduler>();
 
     // Start the lightweight task scheduler thread
     CScheduler::Function serviceLoop = [&node] {
         node.scheduler->serviceQueue();
     };
     threadGroup.create_thread(std::bind(&TraceThread<CScheduler::Function>,
                                         "scheduler", serviceLoop));
 
     // Gather some entropy once per minute.
     node.scheduler->scheduleEvery(
         [] {
             RandAddPeriodic();
             return true;
         },
         std::chrono::minutes{1});
 
     GetMainSignals().RegisterBackgroundSignalScheduler(*node.scheduler);
 
     /**
      * Register RPC commands regardless of -server setting so they will be
      * available in the GUI RPC console even if external calls are disabled.
      */
     RegisterAllRPCCommands(config, rpcServer, tableRPC);
     for (const auto &client : node.chain_clients) {
         client->registerRpcs();
     }
 #if ENABLE_ZMQ
     RegisterZMQRPCCommands(tableRPC);
 #endif
 
     /**
      * Start the RPC server.  It will be started in "warmup" mode and not
      * process calls yet (but it will verify that the server is there and will
      * be ready later).  Warmup mode will be completed when initialisation is
      * finished.
      */
     if (args.GetBoolArg("-server", false)) {
         uiInterface.InitMessage_connect(SetRPCWarmupStatus);
         if (!AppInitServers(config, httpRPCRequestProcessor, node)) {
             return InitError(
                 _("Unable to start HTTP server. See debug log for details."));
         }
     }
 
     // Step 5: verify wallet database integrity
     for (const auto &client : node.chain_clients) {
         if (!client->verify()) {
             return false;
         }
     }
 
     // Step 6: network initialization
 
     // Note that we absolutely cannot open any actual connections
     // until the very end ("start node") as the UTXO/block state
     // is not yet setup and may end up being set up twice if we
     // need to reindex later.
 
     assert(!node.banman);
     node.banman = std::make_unique<BanMan>(
         GetDataDir() / "banlist.dat", config.GetChainParams(), &uiInterface,
         args.GetArg("-bantime", DEFAULT_MISBEHAVING_BANTIME));
     assert(!node.connman);
     node.connman = std::make_unique<CConnman>(
         config, GetRand(std::numeric_limits<uint64_t>::max()),
         GetRand(std::numeric_limits<uint64_t>::max()),
         gArgs.GetBoolArg("-networkactive", true));
 
     // Make mempool generally available in the node context. For example the
     // connection manager, wallet, or RPC threads, which are all started after
     // this, may use it from the node context.
     assert(!node.mempool);
     node.mempool = std::make_unique<CTxMemPool>();
     if (node.mempool) {
         int ratio = std::min<int>(
             std::max<int>(
                 args.GetArg("-checkmempool",
                             chainparams.DefaultConsistencyChecks() ? 1 : 0),
                 0),
             1000000);
         if (ratio != 0) {
             node.mempool->setSanityCheck(1.0 / ratio);
         }
     }
 
     assert(!node.chainman);
     node.chainman = &g_chainman;
     ChainstateManager &chainman = *Assert(node.chainman);
 
     node.peerman.reset(new PeerManager(chainparams, *node.connman,
                                        node.banman.get(), *node.scheduler,
                                        chainman, *node.mempool));
     RegisterValidationInterface(node.peerman.get());
 
     // sanitize comments per BIP-0014, format user agent and check total size
     std::vector<std::string> uacomments;
     for (const std::string &cmt : args.GetArgs("-uacomment")) {
         if (cmt != SanitizeString(cmt, SAFE_CHARS_UA_COMMENT)) {
             return InitError(strprintf(
                 _("User Agent comment (%s) contains unsafe characters."), cmt));
         }
         uacomments.push_back(cmt);
     }
     const std::string client_name = args.GetArg("-uaclientname", CLIENT_NAME);
     const std::string client_version =
         args.GetArg("-uaclientversion", FormatVersion(CLIENT_VERSION));
     if (client_name != SanitizeString(client_name, SAFE_CHARS_UA_COMMENT)) {
         return InitError(strprintf(
             _("-uaclientname (%s) contains invalid characters."), client_name));
     }
     if (client_version !=
         SanitizeString(client_version, SAFE_CHARS_UA_COMMENT)) {
         return InitError(
             strprintf(_("-uaclientversion (%s) contains invalid characters."),
                       client_version));
     }
     const std::string strSubVersion =
         FormatUserAgent(client_name, client_version, uacomments);
     if (strSubVersion.size() > MAX_SUBVERSION_LENGTH) {
         return InitError(strprintf(
             _("Total length of network version string (%i) exceeds maximum "
               "length (%i). Reduce the number or size of uacomments."),
             strSubVersion.size(), MAX_SUBVERSION_LENGTH));
     }
 
     if (args.IsArgSet("-onlynet")) {
         std::set<enum Network> nets;
         for (const std::string &snet : args.GetArgs("-onlynet")) {
             enum Network net = ParseNetwork(snet);
             if (net == NET_UNROUTABLE) {
                 return InitError(strprintf(
                     _("Unknown network specified in -onlynet: '%s'"), snet));
             }
             nets.insert(net);
         }
         for (int n = 0; n < NET_MAX; n++) {
             enum Network net = (enum Network)n;
             if (!nets.count(net)) {
                 SetReachable(net, false);
             }
         }
     }
 
     // Check for host lookup allowed before parsing any network related
     // parameters
     fNameLookup = args.GetBoolArg("-dns", DEFAULT_NAME_LOOKUP);
 
     bool proxyRandomize =
         args.GetBoolArg("-proxyrandomize", DEFAULT_PROXYRANDOMIZE);
     // -proxy sets a proxy for all outgoing network traffic
     // -noproxy (or -proxy=0) as well as the empty string can be used to not set
     // a proxy, this is the default
     std::string proxyArg = args.GetArg("-proxy", "");
     SetReachable(NET_ONION, false);
     if (proxyArg != "" && proxyArg != "0") {
         CService proxyAddr;
         if (!Lookup(proxyArg, proxyAddr, 9050, fNameLookup)) {
             return InitError(strprintf(
                 _("Invalid -proxy address or hostname: '%s'"), proxyArg));
         }
 
         proxyType addrProxy = proxyType(proxyAddr, proxyRandomize);
         if (!addrProxy.IsValid()) {
             return InitError(strprintf(
                 _("Invalid -proxy address or hostname: '%s'"), proxyArg));
         }
 
         SetProxy(NET_IPV4, addrProxy);
         SetProxy(NET_IPV6, addrProxy);
         SetProxy(NET_ONION, addrProxy);
         SetNameProxy(addrProxy);
         // by default, -proxy sets onion as reachable, unless -noonion later
         SetReachable(NET_ONION, true);
     }
 
     // -onion can be used to set only a proxy for .onion, or override normal
     // proxy for .onion addresses.
     // -noonion (or -onion=0) disables connecting to .onion entirely. An empty
     // string is used to not override the onion proxy (in which case it defaults
     // to -proxy set above, or none)
     std::string onionArg = args.GetArg("-onion", "");
     if (onionArg != "") {
         if (onionArg == "0") {
             // Handle -noonion/-onion=0
             SetReachable(NET_ONION, false);
         } else {
             CService onionProxy;
             if (!Lookup(onionArg, onionProxy, 9050, fNameLookup)) {
                 return InitError(strprintf(
                     _("Invalid -onion address or hostname: '%s'"), onionArg));
             }
             proxyType addrOnion = proxyType(onionProxy, proxyRandomize);
             if (!addrOnion.IsValid()) {
                 return InitError(strprintf(
                     _("Invalid -onion address or hostname: '%s'"), onionArg));
             }
             SetProxy(NET_ONION, addrOnion);
             SetReachable(NET_ONION, true);
         }
     }
 
     // see Step 2: parameter interactions for more information about these
     fListen = args.GetBoolArg("-listen", DEFAULT_LISTEN);
     fDiscover = args.GetBoolArg("-discover", true);
     g_relay_txes = !args.GetBoolArg("-blocksonly", DEFAULT_BLOCKSONLY);
 
     for (const std::string &strAddr : args.GetArgs("-externalip")) {
         CService addrLocal;
         if (Lookup(strAddr, addrLocal, GetListenPort(), fNameLookup) &&
             addrLocal.IsValid()) {
             AddLocal(addrLocal, LOCAL_MANUAL);
         } else {
             return InitError(ResolveErrMsg("externalip", strAddr));
         }
     }
 
     // Read asmap file if configured
     if (args.IsArgSet("-asmap")) {
         fs::path asmap_path = fs::path(args.GetArg("-asmap", ""));
         if (asmap_path.empty()) {
             asmap_path = DEFAULT_ASMAP_FILENAME;
         }
         if (!asmap_path.is_absolute()) {
             asmap_path = GetDataDir() / asmap_path;
         }
         if (!fs::exists(asmap_path)) {
             InitError(strprintf(_("Could not find asmap file %s"), asmap_path));
             return false;
         }
         std::vector<bool> asmap = CAddrMan::DecodeAsmap(asmap_path);
         if (asmap.size() == 0) {
             InitError(
                 strprintf(_("Could not parse asmap file %s"), asmap_path));
             return false;
         }
         const uint256 asmap_version = SerializeHash(asmap);
         node.connman->SetAsmap(std::move(asmap));
         LogPrintf("Using asmap version %s for IP bucketing\n",
                   asmap_version.ToString());
     } else {
         LogPrintf("Using /16 prefix for IP bucketing\n");
     }
 
 #if ENABLE_ZMQ
     g_zmq_notification_interface = CZMQNotificationInterface::Create();
 
     if (g_zmq_notification_interface) {
         RegisterValidationInterface(g_zmq_notification_interface);
     }
 #endif
     // unlimited unless -maxuploadtarget is set
     uint64_t nMaxOutboundLimit = 0;
     uint64_t nMaxOutboundTimeframe = MAX_UPLOAD_TIMEFRAME;
 
     if (args.IsArgSet("-maxuploadtarget")) {
         nMaxOutboundLimit =
             args.GetArg("-maxuploadtarget", DEFAULT_MAX_UPLOAD_TARGET) * 1024 *
             1024;
     }
 
     // Step 6.5 (I guess ?): Initialize Avalanche.
     bilingual_str avalancheError;
     g_avalanche = avalanche::Processor::MakeProcessor(
         args, *node.chain, node.connman.get(), avalancheError);
     if (!g_avalanche) {
         InitError(avalancheError);
         return false;
     }
 
     if (isAvalancheEnabled(args) &&
         g_avalanche->isAvalancheServiceAvailable()) {
         nLocalServices = ServiceFlags(nLocalServices | NODE_AVALANCHE);
     }
 
     // Step 7: load block chain
 
     fReindex = args.GetBoolArg("-reindex", false);
     bool fReindexChainState = args.GetBoolArg("-reindex-chainstate", false);
 
     // cache size calculations
     int64_t nTotalCache = (args.GetArg("-dbcache", DEFAULT_DB_CACHE_MB) << 20);
     // total cache cannot be less than MIN_DB_CACHE_MB
     nTotalCache = std::max(nTotalCache, MIN_DB_CACHE_MB << 20);
     // total cache cannot be greater than MAX_DB_CACHE_MB
     nTotalCache = std::min(nTotalCache, MAX_DB_CACHE_MB << 20);
     int64_t nBlockTreeDBCache =
         std::min(nTotalCache / 8, MAX_BLOCK_DB_CACHE_MB << 20);
     nTotalCache -= nBlockTreeDBCache;
     int64_t nTxIndexCache =
         std::min(nTotalCache / 8, args.GetBoolArg("-txindex", DEFAULT_TXINDEX)
                                       ? MAX_TX_INDEX_CACHE_MB << 20
                                       : 0);
     nTotalCache -= nTxIndexCache;
     int64_t filter_index_cache = 0;
     if (!g_enabled_filter_types.empty()) {
         size_t n_indexes = g_enabled_filter_types.size();
         int64_t max_cache =
             std::min(nTotalCache / 8, MAX_FILTER_INDEX_CACHE_MB << 20);
         filter_index_cache = max_cache / n_indexes;
         nTotalCache -= filter_index_cache * n_indexes;
     }
     // use 25%-50% of the remainder for disk cache
     int64_t nCoinDBCache =
         std::min(nTotalCache / 2, (nTotalCache / 4) + (1 << 23));
     // cap total coins db cache
     nCoinDBCache = std::min(nCoinDBCache, MAX_COINS_DB_CACHE_MB << 20);
     nTotalCache -= nCoinDBCache;
     // the rest goes to in-memory cache
     int64_t nCoinCacheUsage = nTotalCache;
     int64_t nMempoolSizeMax =
         args.GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000;
     LogPrintf("Cache configuration:\n");
     LogPrintf("* Using %.1f MiB for block index database\n",
               nBlockTreeDBCache * (1.0 / 1024 / 1024));
     if (args.GetBoolArg("-txindex", DEFAULT_TXINDEX)) {
         LogPrintf("* Using %.1f MiB for transaction index database\n",
                   nTxIndexCache * (1.0 / 1024 / 1024));
     }
     for (BlockFilterType filter_type : g_enabled_filter_types) {
         LogPrintf("* Using %.1f MiB for %s block filter index database\n",
                   filter_index_cache * (1.0 / 1024 / 1024),
                   BlockFilterTypeName(filter_type));
     }
     LogPrintf("* Using %.1f MiB for chain state database\n",
               nCoinDBCache * (1.0 / 1024 / 1024));
     LogPrintf("* Using %.1f MiB for in-memory UTXO set (plus up to %.1f MiB of "
               "unused mempool space)\n",
               nCoinCacheUsage * (1.0 / 1024 / 1024),
               nMempoolSizeMax * (1.0 / 1024 / 1024));
 
     bool fLoaded = false;
     while (!fLoaded && !ShutdownRequested()) {
         const bool fReset = fReindex;
         auto is_coinsview_empty =
             [&](CChainState *chainstate) EXCLUSIVE_LOCKS_REQUIRED(::cs_main) {
                 return fReset || fReindexChainState ||
                        chainstate->CoinsTip().GetBestBlock().IsNull();
             };
         bilingual_str strLoadError;
 
         uiInterface.InitMessage(_("Loading block index...").translated);
         do {
             bool failed_verification = false;
             const int64_t load_block_index_start_time = GetTimeMillis();
             try {
                 LOCK(cs_main);
                 chainman.InitializeChainstate(*Assert(node.mempool));
                 chainman.m_total_coinstip_cache = nCoinCacheUsage;
                 chainman.m_total_coinsdb_cache = nCoinDBCache;
 
                 UnloadBlockIndex(node.mempool.get(), chainman);
 
                 // new CBlockTreeDB tries to delete the existing file, which
                 // fails if it's still open from the previous loop. Close it
                 // first:
                 pblocktree.reset();
                 pblocktree.reset(
                     new CBlockTreeDB(nBlockTreeDBCache, false, fReset));
 
                 if (fReset) {
                     pblocktree->WriteReindexing(true);
                     // If we're reindexing in prune mode, wipe away unusable
                     // block files and all undo data files
                     if (fPruneMode) {
                         CleanupBlockRevFiles();
                     }
                 }
 
                 const Consensus::Params &params = chainparams.GetConsensus();
 
                 // If necessary, upgrade from older database format.
                 // This is a no-op if we cleared the block tree db with -reindex
                 // or -reindex-chainstate
                 if (!pblocktree->Upgrade(params)) {
                     strLoadError = _("Error upgrading block index database");
                     break;
                 }
 
                 if (ShutdownRequested()) {
                     break;
                 }
 
                 // LoadBlockIndex will load fHavePruned if we've ever removed a
                 // block file from disk.
                 // Note that it also sets fReindex based on the disk flag!
                 // From here on out fReindex and fReset mean something
                 // different!
                 if (!chainman.LoadBlockIndex(params)) {
                     if (ShutdownRequested()) {
                         break;
                     }
                     strLoadError = _("Error loading block database");
                     break;
                 }
 
                 // If the loaded chain has a wrong genesis, bail out immediately
                 // (we're likely using a testnet datadir, or the other way
                 // around).
                 if (!chainman.BlockIndex().empty() &&
                     !LookupBlockIndex(params.hashGenesisBlock)) {
                     return InitError(_("Incorrect or no genesis block found. "
                                        "Wrong datadir for network?"));
                 }
 
                 // Check for changed -prune state.  What we are concerned about
                 // is a user who has pruned blocks in the past, but is now
                 // trying to run unpruned.
                 if (fHavePruned && !fPruneMode) {
                     strLoadError =
                         _("You need to rebuild the database using -reindex to "
                           "go back to unpruned mode.  This will redownload the "
                           "entire blockchain");
                     break;
                 }
 
                 // At this point blocktree args are consistent with what's on
                 // disk. If we're not mid-reindex (based on disk + args), add a
                 // genesis block on disk (otherwise we use the one already on
                 // disk).
                 // This is called again in ThreadImport after the reindex
                 // completes.
                 if (!fReindex && !LoadGenesisBlock(chainparams)) {
                     strLoadError = _("Error initializing block database");
                     break;
                 }
 
                 // At this point we're either in reindex or we've loaded a
                 // useful block tree into BlockIndex()!
 
                 bool failed_chainstate_init = false;
 
                 for (CChainState *chainstate : chainman.GetAll()) {
                     LogPrintf("Initializing chainstate %s\n",
                               chainstate->ToString());
                     chainstate->InitCoinsDB(
                         /* cache_size_bytes */ nCoinDBCache,
                         /* in_memory */ false,
                         /* should_wipe */ fReset || fReindexChainState);
 
                     chainstate->CoinsErrorCatcher().AddReadErrCallback([]() {
                         uiInterface.ThreadSafeMessageBox(
                             _("Error reading from database, shutting down."),
                             "", CClientUIInterface::MSG_ERROR);
                     });
 
                     // If necessary, upgrade from older database format.
                     // This is a no-op if we cleared the coinsviewdb with
                     // -reindex or -reindex-chainstate
                     if (!chainstate->CoinsDB().Upgrade()) {
                         strLoadError = _("Error upgrading chainstate database");
                         failed_chainstate_init = true;
                         break;
                     }
 
                     // ReplayBlocks is a no-op if we cleared the coinsviewdb
                     // with -reindex or -reindex-chainstate
                     if (!chainstate->ReplayBlocks(params)) {
                         strLoadError = _(
                             "Unable to replay blocks. You will need to rebuild "
                             "the database using -reindex-chainstate.");
                         failed_chainstate_init = true;
                         break;
                     }
 
                     // The on-disk coinsdb is now in a good state, create the
                     // cache
                     chainstate->InitCoinsCache(nCoinCacheUsage);
                     assert(chainstate->CanFlushToDisk());
 
                     if (!is_coinsview_empty(chainstate)) {
                         // LoadChainTip initializes the chain based on
                         // CoinsTip()'s best block
                         if (!chainstate->LoadChainTip(chainparams)) {
                             strLoadError =
                                 _("Error initializing block database");
                             failed_chainstate_init = true;
                             // out of the per-chainstate loop
                             break;
                         }
                         assert(chainstate->m_chain.Tip() != nullptr);
                     }
                 }
 
                 if (failed_chainstate_init) {
                     // out of the chainstate activation do-while
                     break;
                 }
 
                 for (CChainState *chainstate : chainman.GetAll()) {
                     if (!is_coinsview_empty(chainstate)) {
                         uiInterface.InitMessage(
                             _("Verifying blocks...").translated);
                         if (fHavePruned &&
                             args.GetArg("-checkblocks", DEFAULT_CHECKBLOCKS) >
                                 MIN_BLOCKS_TO_KEEP) {
                             LogPrintf(
                                 "Prune: pruned datadir may not have more than "
                                 "%d blocks; only checking available blocks\n",
                                 MIN_BLOCKS_TO_KEEP);
                         }
 
                         const CBlockIndex *tip = chainstate->m_chain.Tip();
                         RPCNotifyBlockChange(tip);
                         if (tip &&
                             tip->nTime > GetAdjustedTime() + 2 * 60 * 60) {
                             strLoadError =
                                 _("The block database contains a block which "
                                   "appears to be from the future. "
                                   "This may be due to your computer's date and "
                                   "time being set incorrectly. "
                                   "Only rebuild the block database if you are "
                                   "sure that your computer's date and time are "
                                   "correct");
                             failed_verification = true;
                             break;
                         }
 
                         // Only verify the DB of the active chainstate. This is
                         // fixed in later work when we allow VerifyDB to be
                         // parameterized by chainstate.
                         if (&::ChainstateActive() == chainstate &&
                             !CVerifyDB().VerifyDB(
                                 config, &chainstate->CoinsDB(),
                                 args.GetArg("-checklevel", DEFAULT_CHECKLEVEL),
                                 args.GetArg("-checkblocks",
                                             DEFAULT_CHECKBLOCKS))) {
                             strLoadError =
                                 _("Corrupted block database detected");
                             failed_verification = true;
                             break;
                         }
                     }
                 }
             } catch (const std::exception &e) {
                 LogPrintf("%s\n", e.what());
                 strLoadError = _("Error opening block database");
                 failed_verification = true;
                 break;
             }
 
             if (!failed_verification) {
                 fLoaded = true;
                 LogPrintf(" block index %15dms\n",
                           GetTimeMillis() - load_block_index_start_time);
             }
         } while (false);
 
         if (!fLoaded && !ShutdownRequested()) {
             // first suggest a reindex
             if (!fReset) {
                 bool fRet = uiInterface.ThreadSafeQuestion(
                     strLoadError + Untranslated(".\n\n") +
                         _("Do you want to rebuild the block database now?"),
                     strLoadError.original +
                         ".\nPlease restart with -reindex or "
                         "-reindex-chainstate to recover.",
                     "",
                     CClientUIInterface::MSG_ERROR |
                         CClientUIInterface::BTN_ABORT);
                 if (fRet) {
                     fReindex = true;
                     AbortShutdown();
                 } else {
                     LogPrintf("Aborted block database rebuild. Exiting.\n");
                     return false;
                 }
             } else {
                 return InitError(strLoadError);
             }
         }
     }
 
     // As LoadBlockIndex can take several minutes, it's possible the user
     // requested to kill the GUI during the last operation. If so, exit.
     // As the program has not fully started yet, Shutdown() is possibly
     // overkill.
     if (ShutdownRequested()) {
         LogPrintf("Shutdown requested. Exiting.\n");
         return false;
     }
 
     // Encoded addresses using cashaddr instead of base58.
     // We do this by default to avoid confusion with BTC addresses.
     config.SetCashAddrEncoding(args.GetBoolArg("-usecashaddr", true));
 
     // Step 8: load indexers
     if (args.GetBoolArg("-txindex", DEFAULT_TXINDEX)) {
         g_txindex = std::make_unique<TxIndex>(nTxIndexCache, false, fReindex);
         g_txindex->Start();
     }
 
     for (const auto &filter_type : g_enabled_filter_types) {
         InitBlockFilterIndex(filter_type, filter_index_cache, false, fReindex);
         GetBlockFilterIndex(filter_type)->Start();
     }
 
     // Step 9: load wallet
     for (const auto &client : node.chain_clients) {
         if (!client->load()) {
             return false;
         }
     }
 
     // Step 10: data directory maintenance
 
     // if pruning, unset the service bit and perform the initial blockstore
     // prune after any wallet rescanning has taken place.
     if (fPruneMode) {
         LogPrintf("Unsetting NODE_NETWORK on prune mode\n");
         nLocalServices = ServiceFlags(nLocalServices & ~NODE_NETWORK);
         if (!fReindex) {
             LOCK(cs_main);
             for (CChainState *chainstate : chainman.GetAll()) {
                 uiInterface.InitMessage(_("Pruning blockstore...").translated);
                 chainstate->PruneAndFlush();
             }
         }
     }
 
     // Step 11: import blocks
     if (!CheckDiskSpace(GetDataDir())) {
         InitError(
             strprintf(_("Error: Disk space is low for %s"), GetDataDir()));
         return false;
     }
     if (!CheckDiskSpace(GetBlocksDir())) {
         InitError(
             strprintf(_("Error: Disk space is low for %s"), GetBlocksDir()));
         return false;
     }
 
     // Either install a handler to notify us when genesis activates, or set
     // fHaveGenesis directly.
     // No locking, as this happens before any background thread is started.
     boost::signals2::connection block_notify_genesis_wait_connection;
     if (::ChainActive().Tip() == nullptr) {
         block_notify_genesis_wait_connection =
             uiInterface.NotifyBlockTip_connect(
                 std::bind(BlockNotifyGenesisWait, std::placeholders::_2));
     } else {
         fHaveGenesis = true;
     }
 
 #if defined(HAVE_SYSTEM)
     const std::string block_notify = args.GetArg("-blocknotify", "");
     if (!block_notify.empty()) {
         uiInterface.NotifyBlockTip_connect([block_notify](
                                                SynchronizationState sync_state,
                                                const CBlockIndex *pBlockIndex) {
             if (sync_state != SynchronizationState::POST_INIT || !pBlockIndex) {
                 return;
             }
             std::string command = block_notify;
             boost::replace_all(command, "%s",
                                pBlockIndex->GetBlockHash().GetHex());
             std::thread t(runCommand, command);
             // thread runs free
             t.detach();
         });
     }
 #endif
 
     std::vector<fs::path> vImportFiles;
     for (const std::string &strFile : args.GetArgs("-loadblock")) {
         vImportFiles.push_back(strFile);
     }
 
     g_load_block =
         std::thread(&TraceThread<std::function<void()>>, "loadblk",
                     [=, &config, &chainman, &args] {
                         ThreadImport(config, chainman, vImportFiles, args);
                     });
 
     // Wait for genesis block to be processed
     {
         WAIT_LOCK(g_genesis_wait_mutex, lock);
         // We previously could hang here if StartShutdown() is called prior to
         // ThreadImport getting started, so instead we just wait on a timer to
         // check ShutdownRequested() regularly.
         while (!fHaveGenesis && !ShutdownRequested()) {
             g_genesis_wait_cv.wait_for(lock, std::chrono::milliseconds(500));
         }
         block_notify_genesis_wait_connection.disconnect();
     }
 
     if (ShutdownRequested()) {
         return false;
     }
 
     // Step 12: start node
 
     int chain_active_height;
 
     //// debug print
     {
         LOCK(cs_main);
         LogPrintf("block tree size = %u\n", chainman.BlockIndex().size());
         chain_active_height = chainman.ActiveChain().Height();
         if (tip_info) {
             tip_info->block_height = chain_active_height;
             tip_info->block_time =
                 chainman.ActiveChain().Tip()
                     ? chainman.ActiveChain().Tip()->GetBlockTime()
                     : Params().GenesisBlock().GetBlockTime();
             tip_info->verification_progress = GuessVerificationProgress(
                 Params().TxData(), chainman.ActiveChain().Tip());
         }
         if (tip_info && ::pindexBestHeader) {
             tip_info->header_height = ::pindexBestHeader->nHeight;
             tip_info->header_time = ::pindexBestHeader->GetBlockTime();
         }
     }
     LogPrintf("nBestHeight = %d\n", chain_active_height);
 
     if (args.GetBoolArg("-listenonion", DEFAULT_LISTEN_ONION)) {
         StartTorControl();
     }
 
     Discover();
 
     // Map ports with UPnP
     if (args.GetBoolArg("-upnp", DEFAULT_UPNP)) {
         StartMapPort();
     }
 
     CConnman::Options connOptions;
     connOptions.nLocalServices = nLocalServices;
     connOptions.nMaxConnections = nMaxConnections;
     connOptions.m_max_outbound_full_relay = std::min(
         MAX_OUTBOUND_FULL_RELAY_CONNECTIONS, connOptions.nMaxConnections);
     connOptions.m_max_outbound_block_relay = std::min(
         MAX_BLOCK_RELAY_ONLY_CONNECTIONS,
         connOptions.nMaxConnections - connOptions.m_max_outbound_full_relay);
     connOptions.nMaxAddnode = MAX_ADDNODE_CONNECTIONS;
     connOptions.nMaxFeeler = MAX_FEELER_CONNECTIONS;
     connOptions.nBestHeight = chain_active_height;
     connOptions.uiInterface = &uiInterface;
     connOptions.m_banman = node.banman.get();
     connOptions.m_msgproc = node.peerman.get();
     connOptions.nSendBufferMaxSize =
         1000 * args.GetArg("-maxsendbuffer", DEFAULT_MAXSENDBUFFER);
     connOptions.nReceiveFloodSize =
         1000 * args.GetArg("-maxreceivebuffer", DEFAULT_MAXRECEIVEBUFFER);
     connOptions.m_added_nodes = args.GetArgs("-addnode");
 
     connOptions.nMaxOutboundTimeframe = nMaxOutboundTimeframe;
     connOptions.nMaxOutboundLimit = nMaxOutboundLimit;
     connOptions.m_peer_connect_timeout = peer_connect_timeout;
 
     for (const std::string &strBind : args.GetArgs("-bind")) {
         CService addrBind;
         if (!Lookup(strBind, addrBind, GetListenPort(), false)) {
             return InitError(ResolveErrMsg("bind", strBind));
         }
         connOptions.vBinds.push_back(addrBind);
     }
 
     for (const std::string &strBind : args.GetArgs("-whitebind")) {
         NetWhitebindPermissions whitebind;
         bilingual_str error;
         if (!NetWhitebindPermissions::TryParse(strBind, whitebind, error)) {
             return InitError(error);
         }
         connOptions.vWhiteBinds.push_back(whitebind);
     }
 
     for (const auto &net : args.GetArgs("-whitelist")) {
         NetWhitelistPermissions subnet;
         bilingual_str error;
         if (!NetWhitelistPermissions::TryParse(net, subnet, error)) {
             return InitError(error);
         }
         connOptions.vWhitelistedRange.push_back(subnet);
     }
 
     connOptions.vSeedNodes = args.GetArgs("-seednode");
 
     // Initiate outbound connections unless connect=0
     connOptions.m_use_addrman_outgoing = !args.IsArgSet("-connect");
     if (!connOptions.m_use_addrman_outgoing) {
         const auto connect = args.GetArgs("-connect");
         if (connect.size() != 1 || connect[0] != "0") {
             connOptions.m_specified_outgoing = connect;
         }
     }
     if (!node.connman->Start(*node.scheduler, connOptions)) {
         return false;
     }
 
     // Step 13: finished
 
     SetRPCWarmupFinished();
     uiInterface.InitMessage(_("Done loading").translated);
 
     for (const auto &client : node.chain_clients) {
         client->start(*node.scheduler);
     }
 
     BanMan *banman = node.banman.get();
     node.scheduler->scheduleEvery(
         [banman] {
             banman->DumpBanlist();
             return true;
         },
         DUMP_BANS_INTERVAL);
 
     // Start Avalanche's event loop.
     g_avalanche->startEventLoop(*node.scheduler);
 
     return true;
 }
diff --git a/src/interfaces/chain.cpp b/src/interfaces/chain.cpp
index ab3298557..90ccb37ac 100644
--- a/src/interfaces/chain.cpp
+++ b/src/interfaces/chain.cpp
@@ -1,493 +1,496 @@
 // Copyright (c) 2018-2019 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <interfaces/chain.h>
 
 #include <blockdb.h>
 #include <chain.h>
 #include <chainparams.h>
 #include <interfaces/handler.h>
 #include <interfaces/wallet.h>
 #include <net.h>
 #include <net_processing.h>
 #include <node/coin.h>
 #include <node/context.h>
 #include <node/transaction.h>
 #include <node/ui_interface.h>
 #include <policy/mempool.h>
 #include <policy/policy.h>
 #include <policy/settings.h>
 #include <primitives/block.h>
 #include <primitives/blockhash.h>
 #include <rpc/protocol.h>
 #include <rpc/server.h>
 #include <shutdown.h>
 #include <sync.h>
 #include <timedata.h>
 #include <txmempool.h>
 #include <univalue.h>
 #include <util/system.h>
 #include <validation.h>
 #include <validationinterface.h>
 
 #include <utility>
 
 namespace interfaces {
 namespace {
 
     bool FillBlock(const CBlockIndex *index, const FoundBlock &block,
                    UniqueLock<RecursiveMutex> &lock) {
         if (!index) {
             return false;
         }
         if (block.m_hash) {
             *block.m_hash = index->GetBlockHash();
         }
         if (block.m_height) {
             *block.m_height = index->nHeight;
         }
         if (block.m_time) {
             *block.m_time = index->GetBlockTime();
         }
         if (block.m_max_time) {
             *block.m_max_time = index->GetBlockTimeMax();
         }
         if (block.m_mtp_time) {
             *block.m_mtp_time = index->GetMedianTimePast();
         }
         if (block.m_data) {
             REVERSE_LOCK(lock);
             if (!ReadBlockFromDisk(*block.m_data, index,
                                    Params().GetConsensus())) {
                 block.m_data->SetNull();
             }
         }
         return true;
     }
 
     class NotificationsProxy : public CValidationInterface {
     public:
         explicit NotificationsProxy(
             std::shared_ptr<Chain::Notifications> notifications)
             : m_notifications(std::move(notifications)) {}
         virtual ~NotificationsProxy() = default;
-        void TransactionAddedToMempool(const CTransactionRef &tx) override {
-            m_notifications->transactionAddedToMempool(tx);
+        void TransactionAddedToMempool(const CTransactionRef &tx,
+                                       uint64_t mempool_sequence) override {
+            m_notifications->transactionAddedToMempool(tx, mempool_sequence);
         }
-        void
-        TransactionRemovedFromMempool(const CTransactionRef &tx,
-                                      MemPoolRemovalReason reason) override {
-            m_notifications->transactionRemovedFromMempool(tx, reason);
+        void TransactionRemovedFromMempool(const CTransactionRef &tx,
+                                           MemPoolRemovalReason reason,
+                                           uint64_t mempool_sequence) override {
+            m_notifications->transactionRemovedFromMempool(tx, reason,
+                                                           mempool_sequence);
         }
         void BlockConnected(const std::shared_ptr<const CBlock> &block,
                             const CBlockIndex *index) override {
             m_notifications->blockConnected(*block, index->nHeight);
         }
         void BlockDisconnected(const std::shared_ptr<const CBlock> &block,
                                const CBlockIndex *index) override {
             m_notifications->blockDisconnected(*block, index->nHeight);
         }
         void UpdatedBlockTip(const CBlockIndex *index,
                              const CBlockIndex *fork_index,
                              bool is_ibd) override {
             m_notifications->updatedBlockTip();
         }
         void ChainStateFlushed(const CBlockLocator &locator) override {
             m_notifications->chainStateFlushed(locator);
         }
         std::shared_ptr<Chain::Notifications> m_notifications;
     };
 
     class NotificationsHandlerImpl : public Handler {
     public:
         explicit NotificationsHandlerImpl(
             std::shared_ptr<Chain::Notifications> notifications)
             : m_proxy(std::make_shared<NotificationsProxy>(
                   std::move(notifications))) {
             RegisterSharedValidationInterface(m_proxy);
         }
         ~NotificationsHandlerImpl() override { disconnect(); }
         void disconnect() override {
             if (m_proxy) {
                 UnregisterSharedValidationInterface(m_proxy);
                 m_proxy.reset();
             }
         }
         std::shared_ptr<NotificationsProxy> m_proxy;
     };
 
     class RpcHandlerImpl : public Handler {
     public:
         explicit RpcHandlerImpl(const CRPCCommand &command)
             : m_command(command), m_wrapped_command(&command) {
             m_command.actor = [this](const Config &config,
                                      const JSONRPCRequest &request,
                                      UniValue &result, bool last_handler) {
                 if (!m_wrapped_command) {
                     return false;
                 }
                 try {
                     return m_wrapped_command->actor(config, request, result,
                                                     last_handler);
                 } catch (const UniValue &e) {
                     // If this is not the last handler and a wallet not found
                     // exception was thrown, return false so the next handler
                     // can try to handle the request. Otherwise, reraise the
                     // exception.
                     if (!last_handler) {
                         const UniValue &code = e["code"];
                         if (code.isNum() &&
                             code.get_int() == RPC_WALLET_NOT_FOUND) {
                             return false;
                         }
                     }
                     throw;
                 }
             };
             ::tableRPC.appendCommand(m_command.name, &m_command);
         }
 
         void disconnect() final {
             if (m_wrapped_command) {
                 m_wrapped_command = nullptr;
                 ::tableRPC.removeCommand(m_command.name, &m_command);
             }
         }
 
         ~RpcHandlerImpl() override { disconnect(); }
 
         CRPCCommand m_command;
         const CRPCCommand *m_wrapped_command;
     };
 
     class ChainImpl : public Chain {
     public:
         explicit ChainImpl(NodeContext &node, const CChainParams &params)
             : m_node(node), m_params(params) {}
         std::optional<int> getHeight() override {
             LOCK(::cs_main);
             int height = ::ChainActive().Height();
             if (height >= 0) {
                 return height;
             }
             return std::nullopt;
         }
         std::optional<int> getBlockHeight(const BlockHash &hash) override {
             LOCK(::cs_main);
             CBlockIndex *block = LookupBlockIndex(hash);
             if (block && ::ChainActive().Contains(block)) {
                 return block->nHeight;
             }
             return std::nullopt;
         }
         BlockHash getBlockHash(int height) override {
             LOCK(::cs_main);
             CBlockIndex *block = ::ChainActive()[height];
             assert(block);
             return block->GetBlockHash();
         }
         bool haveBlockOnDisk(int height) override {
             LOCK(cs_main);
             CBlockIndex *block = ::ChainActive()[height];
             return block && (block->nStatus.hasData() != 0) && block->nTx > 0;
         }
         std::optional<int>
         findFirstBlockWithTimeAndHeight(int64_t time, int height,
                                         BlockHash *hash) override {
             LOCK(cs_main);
             CBlockIndex *block =
                 ::ChainActive().FindEarliestAtLeast(time, height);
             if (block) {
                 if (hash) {
                     *hash = block->GetBlockHash();
                 }
                 return block->nHeight;
             }
             return std::nullopt;
         }
         CBlockLocator getTipLocator() override {
             LOCK(cs_main);
             return ::ChainActive().GetLocator();
         }
         bool contextualCheckTransactionForCurrentBlock(
             const CTransaction &tx, TxValidationState &state) override {
             LOCK(cs_main);
             return ContextualCheckTransactionForCurrentBlock(
                 m_params.GetConsensus(), tx, state);
         }
         std::optional<int>
         findLocatorFork(const CBlockLocator &locator) override {
             LOCK(cs_main);
             if (CBlockIndex *fork =
                     FindForkInGlobalIndex(::ChainActive(), locator)) {
                 return fork->nHeight;
             }
             return std::nullopt;
         }
         bool findBlock(const BlockHash &hash,
                        const FoundBlock &block) override {
             WAIT_LOCK(cs_main, lock);
             return FillBlock(LookupBlockIndex(hash), block, lock);
         }
         bool findFirstBlockWithTimeAndHeight(int64_t min_time, int min_height,
                                              const FoundBlock &block) override {
             WAIT_LOCK(cs_main, lock);
             return FillBlock(
                 ChainActive().FindEarliestAtLeast(min_time, min_height), block,
                 lock);
         }
         bool findNextBlock(const BlockHash &block_hash, int block_height,
                            const FoundBlock &next, bool *reorg) override {
             WAIT_LOCK(cs_main, lock);
             CBlockIndex *block = ChainActive()[block_height];
             if (block && block->GetBlockHash() != block_hash) {
                 block = nullptr;
             }
             if (reorg) {
                 *reorg = !block;
             }
             return FillBlock(block ? ChainActive()[block_height + 1] : nullptr,
                              next, lock);
         }
         bool findAncestorByHeight(const BlockHash &block_hash,
                                   int ancestor_height,
                                   const FoundBlock &ancestor_out) override {
             WAIT_LOCK(cs_main, lock);
             if (const CBlockIndex *block = LookupBlockIndex(block_hash)) {
                 if (const CBlockIndex *ancestor =
                         block->GetAncestor(ancestor_height)) {
                     return FillBlock(ancestor, ancestor_out, lock);
                 }
             }
             return FillBlock(nullptr, ancestor_out, lock);
         }
         bool findAncestorByHash(const BlockHash &block_hash,
                                 const BlockHash &ancestor_hash,
                                 const FoundBlock &ancestor_out) override {
             WAIT_LOCK(cs_main, lock);
             const CBlockIndex *block = LookupBlockIndex(block_hash);
             const CBlockIndex *ancestor = LookupBlockIndex(ancestor_hash);
             if (block && ancestor &&
                 block->GetAncestor(ancestor->nHeight) != ancestor) {
                 ancestor = nullptr;
             }
             return FillBlock(ancestor, ancestor_out, lock);
         }
         bool findCommonAncestor(const BlockHash &block_hash1,
                                 const BlockHash &block_hash2,
                                 const FoundBlock &ancestor_out,
                                 const FoundBlock &block1_out,
                                 const FoundBlock &block2_out) override {
             WAIT_LOCK(cs_main, lock);
             const CBlockIndex *block1 = LookupBlockIndex(block_hash1);
             const CBlockIndex *block2 = LookupBlockIndex(block_hash2);
             const CBlockIndex *ancestor =
                 block1 && block2 ? LastCommonAncestor(block1, block2) : nullptr;
             // Using & instead of && below to avoid short circuiting and leaving
             // output uninitialized.
             return FillBlock(ancestor, ancestor_out, lock) &
                    FillBlock(block1, block1_out, lock) &
                    FillBlock(block2, block2_out, lock);
         }
         void findCoins(std::map<COutPoint, Coin> &coins) override {
             return FindCoins(m_node, coins);
         }
         double guessVerificationProgress(const BlockHash &block_hash) override {
             LOCK(cs_main);
             return GuessVerificationProgress(Params().TxData(),
                                              LookupBlockIndex(block_hash));
         }
         bool hasBlocks(const BlockHash &block_hash, int min_height,
                        std::optional<int> max_height) override {
             // hasBlocks returns true if all ancestors of block_hash in
             // specified range have block data (are not pruned), false if any
             // ancestors in specified range are missing data.
             //
             // For simplicity and robustness, min_height and max_height are only
             // used to limit the range, and passing min_height that's too low or
             // max_height that's too high will not crash or change the result.
             LOCK(::cs_main);
             if (CBlockIndex *block = LookupBlockIndex(block_hash)) {
                 if (max_height && block->nHeight >= *max_height) {
                     block = block->GetAncestor(*max_height);
                 }
                 for (; block->nStatus.hasData(); block = block->pprev) {
                     // Check pprev to not segfault if min_height is too low
                     if (block->nHeight <= min_height || !block->pprev) {
                         return true;
                     }
                 }
             }
             return false;
         }
         bool hasDescendantsInMempool(const TxId &txid) override {
             if (!m_node.mempool) {
                 return false;
             }
             LOCK(m_node.mempool->cs);
             auto it = m_node.mempool->GetIter(txid);
             return it && (*it)->GetCountWithDescendants() > 1;
         }
         bool broadcastTransaction(const Config &config,
                                   const CTransactionRef &tx,
                                   const Amount &max_tx_fee, bool relay,
                                   std::string &err_string) override {
             const TransactionError err = BroadcastTransaction(
                 m_node, config, tx, err_string, max_tx_fee, relay,
                 /*wait_callback*/ false);
             // Chain clients only care about failures to accept the tx to the
             // mempool. Disregard non-mempool related failures. Note: this will
             // need to be updated if BroadcastTransactions() is updated to
             // return other non-mempool failures that Chain clients do not need
             // to know about.
             return err == TransactionError::OK;
         }
         void getTransactionAncestry(const TxId &txid, size_t &ancestors,
                                     size_t &descendants) override {
             ancestors = descendants = 0;
             if (!m_node.mempool) {
                 return;
             }
             m_node.mempool->GetTransactionAncestry(txid, ancestors,
                                                    descendants);
         }
         void getPackageLimits(size_t &limit_ancestor_count,
                               size_t &limit_descendant_count) override {
             limit_ancestor_count = size_t(
                 std::max<int64_t>(1, gArgs.GetArg("-limitancestorcount",
                                                   DEFAULT_ANCESTOR_LIMIT)));
             limit_descendant_count = size_t(
                 std::max<int64_t>(1, gArgs.GetArg("-limitdescendantcount",
                                                   DEFAULT_DESCENDANT_LIMIT)));
         }
         bool checkChainLimits(const CTransactionRef &tx) override {
             if (!m_node.mempool) {
                 return true;
             }
             LockPoints lp;
             CTxMemPoolEntry entry(tx, Amount(), 0, 0, false, 0, lp);
             CTxMemPool::setEntries ancestors;
             auto limit_ancestor_count =
                 gArgs.GetArg("-limitancestorcount", DEFAULT_ANCESTOR_LIMIT);
             auto limit_ancestor_size =
                 gArgs.GetArg("-limitancestorsize",
                              DEFAULT_ANCESTOR_SIZE_LIMIT) *
                 1000;
             auto limit_descendant_count =
                 gArgs.GetArg("-limitdescendantcount", DEFAULT_DESCENDANT_LIMIT);
             auto limit_descendant_size =
                 gArgs.GetArg("-limitdescendantsize",
                              DEFAULT_DESCENDANT_SIZE_LIMIT) *
                 1000;
             std::string unused_error_string;
             LOCK(m_node.mempool->cs);
             return m_node.mempool->CalculateMemPoolAncestors(
                 entry, ancestors, limit_ancestor_count, limit_ancestor_size,
                 limit_descendant_count, limit_descendant_size,
                 unused_error_string);
         }
         CFeeRate estimateFee() const override {
             if (!m_node.mempool) {
                 return {};
             }
             return m_node.mempool->estimateFee();
         }
         CFeeRate relayMinFee() override { return ::minRelayTxFee; }
         CFeeRate relayDustFee() override { return ::dustRelayFee; }
         bool havePruned() override {
             LOCK(cs_main);
             return ::fHavePruned;
         }
         bool isReadyToBroadcast() override {
             return !::fImporting && !::fReindex && !isInitialBlockDownload();
         }
         bool isInitialBlockDownload() override {
             return ::ChainstateActive().IsInitialBlockDownload();
         }
         bool shutdownRequested() override { return ShutdownRequested(); }
         int64_t getAdjustedTime() override { return GetAdjustedTime(); }
         void initMessage(const std::string &message) override {
             ::uiInterface.InitMessage(message);
         }
         void initWarning(const bilingual_str &message) override {
             InitWarning(message);
         }
         void initError(const bilingual_str &message) override {
             InitError(message);
         }
         void showProgress(const std::string &title, int progress,
                           bool resume_possible) override {
             ::uiInterface.ShowProgress(title, progress, resume_possible);
         }
         std::unique_ptr<Handler> handleNotifications(
             std::shared_ptr<Notifications> notifications) override {
             return std::make_unique<NotificationsHandlerImpl>(
                 std::move(notifications));
         }
         void
         waitForNotificationsIfTipChanged(const BlockHash &old_tip) override {
             if (!old_tip.IsNull()) {
                 LOCK(::cs_main);
                 if (old_tip == ::ChainActive().Tip()->GetBlockHash()) {
                     return;
                 }
             }
             SyncWithValidationInterfaceQueue();
         }
 
         std::unique_ptr<Handler>
         handleRpc(const CRPCCommand &command) override {
             return std::make_unique<RpcHandlerImpl>(command);
         }
         bool rpcEnableDeprecated(const std::string &method) override {
             return IsDeprecatedRPCEnabled(gArgs, method);
         }
         void rpcRunLater(const std::string &name, std::function<void()> fn,
                          int64_t seconds) override {
             RPCRunLater(name, std::move(fn), seconds);
         }
         int rpcSerializationFlags() override { return RPCSerializationFlags(); }
         util::SettingsValue getRwSetting(const std::string &name) override {
             util::SettingsValue result;
             gArgs.LockSettings([&](const util::Settings &settings) {
                 if (const util::SettingsValue *value =
                         util::FindKey(settings.rw_settings, name)) {
                     result = *value;
                 }
             });
             return result;
         }
         bool updateRwSetting(const std::string &name,
                              const util::SettingsValue &value) override {
             gArgs.LockSettings([&](util::Settings &settings) {
                 if (value.isNull()) {
                     settings.rw_settings.erase(name);
                 } else {
                     settings.rw_settings[name] = value;
                 }
             });
             return gArgs.WriteSettingsFile();
         }
         void requestMempoolTransactions(Notifications &notifications) override {
             if (!m_node.mempool) {
                 return;
             }
             LOCK2(::cs_main, m_node.mempool->cs);
             for (const CTxMemPoolEntry &entry : m_node.mempool->mapTx) {
-                notifications.transactionAddedToMempool(entry.GetSharedTx());
+                notifications.transactionAddedToMempool(
+                    entry.GetSharedTx(), 0 /* mempool_sequence */);
             }
         }
         const CChainParams &params() const override { return m_params; }
         NodeContext &m_node;
         const CChainParams &m_params;
     };
 
 } // namespace
 
 std::unique_ptr<Chain> MakeChain(NodeContext &node,
                                  const CChainParams &params) {
     return std::make_unique<ChainImpl>(node, params);
 }
 
 } // namespace interfaces
diff --git a/src/interfaces/chain.h b/src/interfaces/chain.h
index 92aa4720b..1c0056bec 100644
--- a/src/interfaces/chain.h
+++ b/src/interfaces/chain.h
@@ -1,363 +1,364 @@
 // Copyright (c) 2018-2019 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #ifndef BITCOIN_INTERFACES_CHAIN_H
 #define BITCOIN_INTERFACES_CHAIN_H
 
 #include <primitives/transaction.h>
 #include <primitives/txid.h>
 #include <util/settings.h> // For util::SettingsValue
 
 #include <cstddef>
 #include <cstdint>
 #include <functional>
 #include <memory>
 #include <optional>
 #include <string>
 #include <vector>
 
 class ArgsManager;
 class CBlock;
 class CChainParams;
 class Coin;
 class Config;
 class CRPCCommand;
 class CScheduler;
 class TxValidationState;
 
 enum class MemPoolRemovalReason;
 
 struct BlockHash;
 struct bilingual_str;
 struct CBlockLocator;
 struct NodeContext;
 
 namespace Consensus {
 struct Params;
 }
 
 namespace interfaces {
 
 class Handler;
 class Wallet;
 
 //! Helper for findBlock to selectively return pieces of block data.
 class FoundBlock {
 public:
     FoundBlock &hash(BlockHash &hash) {
         m_hash = &hash;
         return *this;
     }
     FoundBlock &height(int &height) {
         m_height = &height;
         return *this;
     }
     FoundBlock &time(int64_t &time) {
         m_time = &time;
         return *this;
     }
     FoundBlock &maxTime(int64_t &max_time) {
         m_max_time = &max_time;
         return *this;
     }
     FoundBlock &mtpTime(int64_t &mtp_time) {
         m_mtp_time = &mtp_time;
         return *this;
     }
     //! Read block data from disk. If the block exists but doesn't have data
     //! (for example due to pruning), the CBlock variable will be set to null.
     FoundBlock &data(CBlock &data) {
         m_data = &data;
         return *this;
     }
 
     BlockHash *m_hash = nullptr;
     int *m_height = nullptr;
     int64_t *m_time = nullptr;
     int64_t *m_max_time = nullptr;
     int64_t *m_mtp_time = nullptr;
     CBlock *m_data = nullptr;
 };
 
 //! Interface giving clients (wallet processes, maybe other analysis tools in
 //! the future) ability to access to the chain state, receive notifications,
 //! estimate fees, and submit transactions.
 //!
 //! TODO: Current chain methods are too low level, exposing too much of the
 //! internal workings of the bitcoin node, and not being very convenient to use.
 //! Chain methods should be cleaned up and simplified over time. Examples:
 //!
 //! * The initMessages() and showProgress() methods which the wallet uses to
 //! send
 //!   notifications to the GUI should go away when GUI and wallet can directly
 //!   communicate with each other without going through the node
 //!   (https://github.com/bitcoin/bitcoin/pull/15288#discussion_r253321096).
 //!
 //! * The handleRpc, registerRpcs, rpcEnableDeprecated methods and other RPC
 //!   methods can go away if wallets listen for HTTP requests on their own
 //!   ports instead of registering to handle requests on the node HTTP port.
 //!
 //! * Move fee estimation queries to an asynchronous interface and let the
 //!   wallet cache it, fee estimation being driven by node mempool, wallet
 //!   should be the consumer.
 //!
 //! * The `guessVerificationProgress`, `getBlockHeight`, `getBlockHash`, etc
 //!   methods can go away if rescan logic is moved on the node side, and wallet
 //!   only register rescan request.
 class Chain {
 public:
     virtual ~Chain() {}
 
     //! Get current chain height, not including genesis block (returns 0 if
     //! chain only contains genesis block, std::nullopt if chain does not
     //! contain any blocks)
     virtual std::optional<int> getHeight() = 0;
 
     //! Get block height above genesis block. Returns 0 for genesis block,
     //! 1 for following block, and so on. Returns std::nullopt for a block not
     //! included in the current chain.
     virtual std::optional<int> getBlockHeight(const BlockHash &hash) = 0;
 
     //! Get block hash. Height must be valid or this function will abort.
     virtual BlockHash getBlockHash(int height) = 0;
 
     //! Check that the block is available on disk (i.e. has not been
     //! pruned), and contains transactions.
     virtual bool haveBlockOnDisk(int height) = 0;
 
     //! Return height of the first block in the chain with timestamp equal
     //! or greater than the given time and height equal or greater than the
     //! given height, or std::nullopt if there is no block with a high enough
     //! timestamp and height. Also return the block hash as an optional output
     //! parameter (to avoid the cost of a second lookup in case this information
     //! is needed.)
     virtual std::optional<int>
     findFirstBlockWithTimeAndHeight(int64_t time, int height,
                                     BlockHash *hash) = 0;
 
     //! Get locator for the current chain tip.
     virtual CBlockLocator getTipLocator() = 0;
 
     //! Return height of the highest block on chain in common with the locator,
     //! which will either be the original block used to create the locator,
     //! or one of its ancestors.
     virtual std::optional<int>
     findLocatorFork(const CBlockLocator &locator) = 0;
 
     //! Check if transaction will be final given chain height current time.
     virtual bool
     contextualCheckTransactionForCurrentBlock(const CTransaction &tx,
                                               TxValidationState &state) = 0;
 
     //! Return whether node has the block and optionally return block metadata
     //! or contents.
     virtual bool findBlock(const BlockHash &hash,
                            const FoundBlock &block = {}) = 0;
 
     //! Find first block in the chain with timestamp >= the given time
     //! and height >= than the given height, return false if there is no block
     //! with a high enough timestamp and height. Optionally return block
     //! information.
     virtual bool
     findFirstBlockWithTimeAndHeight(int64_t min_time, int min_height,
                                     const FoundBlock &block = {}) = 0;
 
     //! Find next block if block is part of current chain. Also flag if
     //! there was a reorg and the specified block hash is no longer in the
     //! current chain, and optionally return block information.
     virtual bool findNextBlock(const BlockHash &block_hash, int block_height,
                                const FoundBlock &next = {},
                                bool *reorg = nullptr) = 0;
 
     //! Find ancestor of block at specified height and optionally return
     //! ancestor information.
     virtual bool findAncestorByHeight(const BlockHash &block_hash,
                                       int ancestor_height,
                                       const FoundBlock &ancestor_out = {}) = 0;
 
     //! Return whether block descends from a specified ancestor, and
     //! optionally return ancestor information.
     virtual bool findAncestorByHash(const BlockHash &block_hash,
                                     const BlockHash &ancestor_hash,
                                     const FoundBlock &ancestor_out = {}) = 0;
 
     //! Find most recent common ancestor between two blocks and optionally
     //! return block information.
     virtual bool findCommonAncestor(const BlockHash &block_hash1,
                                     const BlockHash &block_hash2,
                                     const FoundBlock &ancestor_out = {},
                                     const FoundBlock &block1_out = {},
                                     const FoundBlock &block2_out = {}) = 0;
 
     //! Look up unspent output information. Returns coins in the mempool and in
     //! the current chain UTXO set. Iterates through all the keys in the map and
     //! populates the values.
     virtual void findCoins(std::map<COutPoint, Coin> &coins) = 0;
 
     //! Estimate fraction of total transactions verified if blocks up to
     //! the specified block hash are verified.
     virtual double guessVerificationProgress(const BlockHash &block_hash) = 0;
 
     //! Return true if data is available for all blocks in the specified range
     //! of blocks. This checks all blocks that are ancestors of block_hash in
     //! the height range from min_height to max_height, inclusive.
     virtual bool hasBlocks(const BlockHash &block_hash, int min_height = 0,
                            std::optional<int> max_height = {}) = 0;
 
     //! Check if transaction has descendants in mempool.
     virtual bool hasDescendantsInMempool(const TxId &txid) = 0;
 
     //! Transaction is added to memory pool, if the transaction fee is below the
     //! amount specified by max_tx_fee, and broadcast to all peers if relay is
     //! set to true. Return false if the transaction could not be added due to
     //! the fee or for another reason.
     virtual bool broadcastTransaction(const Config &config,
                                       const CTransactionRef &tx,
                                       const Amount &max_tx_fee, bool relay,
                                       std::string &err_string) = 0;
 
     //! Calculate mempool ancestor and descendant counts for the given
     //! transaction.
     virtual void getTransactionAncestry(const TxId &txid, size_t &ancestors,
                                         size_t &descendants) = 0;
 
     //! Get the node's package limits.
     //! Currently only returns the ancestor and descendant count limits, but
     //! could be enhanced to return more policy settings.
     virtual void getPackageLimits(size_t &limit_ancestor_count,
                                   size_t &limit_descendant_count) = 0;
 
     //! Check if transaction will pass the mempool's chain limits.
     virtual bool checkChainLimits(const CTransactionRef &tx) = 0;
 
     //! Estimate fee
     virtual CFeeRate estimateFee() const = 0;
 
     //! Relay current minimum fee (from -minrelaytxfee settings).
     virtual CFeeRate relayMinFee() = 0;
 
     //! Relay dust fee setting (-dustrelayfee), reflecting lowest rate it's
     //! economical to spend.
     virtual CFeeRate relayDustFee() = 0;
 
     //! Check if any block has been pruned.
     virtual bool havePruned() = 0;
 
     //! Check if the node is ready to broadcast transactions.
     virtual bool isReadyToBroadcast() = 0;
 
     //! Check if in IBD.
     virtual bool isInitialBlockDownload() = 0;
 
     //! Check if shutdown requested.
     virtual bool shutdownRequested() = 0;
 
     //! Get adjusted time.
     virtual int64_t getAdjustedTime() = 0;
 
     //! Send init message.
     virtual void initMessage(const std::string &message) = 0;
 
     //! Send init warning.
     virtual void initWarning(const bilingual_str &message) = 0;
 
     //! Send init error.
     virtual void initError(const bilingual_str &message) = 0;
 
     //! Send progress indicator.
     virtual void showProgress(const std::string &title, int progress,
                               bool resume_possible) = 0;
 
     //! Chain notifications.
     class Notifications {
     public:
         virtual ~Notifications() {}
-        virtual void transactionAddedToMempool(const CTransactionRef &tx) {}
-        virtual void
-        transactionRemovedFromMempool(const CTransactionRef &ptx,
-                                      MemPoolRemovalReason reason) {}
+        virtual void transactionAddedToMempool(const CTransactionRef &tx,
+                                               uint64_t mempool_sequence) {}
+        virtual void transactionRemovedFromMempool(const CTransactionRef &ptx,
+                                                   MemPoolRemovalReason reason,
+                                                   uint64_t mempool_sequence) {}
         virtual void blockConnected(const CBlock &block, int height) {}
         virtual void blockDisconnected(const CBlock &block, int height) {}
         virtual void updatedBlockTip() {}
         virtual void chainStateFlushed(const CBlockLocator &locator) {}
     };
 
     //! Register handler for notifications.
     virtual std::unique_ptr<Handler>
     handleNotifications(std::shared_ptr<Notifications> notifications) = 0;
 
     //! Wait for pending notifications to be processed unless block hash points
     //! to the current chain tip.
     virtual void waitForNotificationsIfTipChanged(const BlockHash &old_tip) = 0;
 
     //! Register handler for RPC. Command is not copied, so reference
     //! needs to remain valid until Handler is disconnected.
     virtual std::unique_ptr<Handler> handleRpc(const CRPCCommand &command) = 0;
 
     //! Check if deprecated RPC is enabled.
     virtual bool rpcEnableDeprecated(const std::string &method) = 0;
 
     //! Run function after given number of seconds. Cancel any previous calls
     //! with same name.
     virtual void rpcRunLater(const std::string &name, std::function<void()> fn,
                              int64_t seconds) = 0;
 
     //! Current RPC serialization flags.
     virtual int rpcSerializationFlags() = 0;
 
     //! Return <datadir>/settings.json setting value.
     virtual util::SettingsValue getRwSetting(const std::string &name) = 0;
 
     //! Write a setting to <datadir>/settings.json.
     virtual bool updateRwSetting(const std::string &name,
                                  const util::SettingsValue &value) = 0;
 
     //! Synchronously send transactionAddedToMempool notifications about all
     //! current mempool transactions to the specified handler and return after
     //! the last one is sent. These notifications aren't coordinated with async
     //! notifications sent by handleNotifications, so out of date async
     //! notifications from handleNotifications can arrive during and after
     //! synchronous notifications from requestMempoolTransactions. Clients need
     //! to be prepared to handle this by ignoring notifications about unknown
     //! removed transactions and already added new transactions.
     virtual void requestMempoolTransactions(Notifications &notifications) = 0;
 
     //! This Chain's parameters
     virtual const CChainParams &params() const = 0;
 };
 
 //! Interface to let node manage chain clients (wallets, or maybe tools for
 //! monitoring and analysis in the future).
 class ChainClient {
 public:
     virtual ~ChainClient() {}
 
     //! Register rpcs.
     virtual void registerRpcs() = 0;
 
     //! Check for errors before loading.
     virtual bool verify() = 0;
 
     //! Load saved state.
     virtual bool load() = 0;
 
     //! Start client execution and provide a scheduler.
     virtual void start(CScheduler &scheduler) = 0;
 
     //! Save state to disk.
     virtual void flush() = 0;
 
     //! Shut down client.
     virtual void stop() = 0;
 
     //! Set mock time.
     virtual void setMockTime(int64_t time) = 0;
 };
 
 //! Return implementation of Chain interface.
 std::unique_ptr<Chain> MakeChain(NodeContext &node, const CChainParams &params);
 
 } // namespace interfaces
 
 #endif // BITCOIN_INTERFACES_CHAIN_H
diff --git a/src/rpc/blockchain.cpp b/src/rpc/blockchain.cpp
index 420ec51c0..10651a6ab 100644
--- a/src/rpc/blockchain.cpp
+++ b/src/rpc/blockchain.cpp
@@ -1,3065 +1,3106 @@
 // Copyright (c) 2010 Satoshi Nakamoto
 // Copyright (c) 2009-2019 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <rpc/blockchain.h>
 
 #include <amount.h>
 #include <blockdb.h>
 #include <blockfilter.h>
 #include <chain.h>
 #include <chainparams.h>
 #include <checkpoints.h>
 #include <coins.h>
 #include <config.h>
 #include <consensus/validation.h>
 #include <core_io.h>
 #include <hash.h>
 #include <index/blockfilterindex.h>
 #include <network.h>
 #include <node/coinstats.h>
 #include <node/context.h>
 #include <node/utxo_snapshot.h>
 #include <policy/policy.h>
 #include <primitives/transaction.h>
 #include <rpc/server.h>
 #include <rpc/util.h>
 #include <script/descriptor.h>
 #include <streams.h>
 #include <txdb.h>
 #include <txmempool.h>
 #include <undo.h>
 #include <util/ref.h>
 #include <util/strencodings.h>
 #include <util/system.h>
 #include <util/translation.h>
 #include <validation.h>
 #include <validationinterface.h>
 #include <versionbitsinfo.h> // For VersionBitsDeploymentInfo
 #include <warnings.h>
 
 #include <condition_variable>
 #include <cstdint>
 #include <memory>
 #include <mutex>
 
 struct CUpdatedBlock {
     BlockHash hash;
     int height;
 };
 
 static Mutex cs_blockchange;
 static std::condition_variable cond_blockchange;
 static CUpdatedBlock latestblock GUARDED_BY(cs_blockchange);
 
 NodeContext &EnsureNodeContext(const util::Ref &context) {
     if (!context.Has<NodeContext>()) {
         throw JSONRPCError(RPC_INTERNAL_ERROR, "Node context not found");
     }
     return context.Get<NodeContext>();
 }
 
 CTxMemPool &EnsureMemPool(const util::Ref &context) {
     NodeContext &node = EnsureNodeContext(context);
     if (!node.mempool) {
         throw JSONRPCError(RPC_CLIENT_MEMPOOL_DISABLED,
                            "Mempool disabled or instance not found");
     }
     return *node.mempool;
 }
 
 ChainstateManager &EnsureChainman(const util::Ref &context) {
     NodeContext &node = EnsureNodeContext(context);
     if (!node.chainman) {
         throw JSONRPCError(RPC_INTERNAL_ERROR, "Node chainman not found");
     }
     return *node.chainman;
 }
 
 /**
  * Calculate the difficulty for a given block index.
  */
 double GetDifficulty(const CBlockIndex *blockindex) {
     CHECK_NONFATAL(blockindex);
 
     int nShift = (blockindex->nBits >> 24) & 0xff;
     double dDiff = double(0x0000ffff) / double(blockindex->nBits & 0x00ffffff);
 
     while (nShift < 29) {
         dDiff *= 256.0;
         nShift++;
     }
     while (nShift > 29) {
         dDiff /= 256.0;
         nShift--;
     }
 
     return dDiff;
 }
 
 static int ComputeNextBlockAndDepth(const CBlockIndex *tip,
                                     const CBlockIndex *blockindex,
                                     const CBlockIndex *&next) {
     next = tip->GetAncestor(blockindex->nHeight + 1);
     if (next && next->pprev == blockindex) {
         return tip->nHeight - blockindex->nHeight + 1;
     }
     next = nullptr;
     return blockindex == tip ? 1 : -1;
 }
 
 UniValue blockheaderToJSON(const CBlockIndex *tip,
                            const CBlockIndex *blockindex) {
     // Serialize passed information without accessing chain state of the active
     // chain!
     // For performance reasons
     AssertLockNotHeld(cs_main);
 
     UniValue result(UniValue::VOBJ);
     result.pushKV("hash", blockindex->GetBlockHash().GetHex());
     const CBlockIndex *pnext;
     int confirmations = ComputeNextBlockAndDepth(tip, blockindex, pnext);
     result.pushKV("confirmations", confirmations);
     result.pushKV("height", blockindex->nHeight);
     result.pushKV("version", blockindex->nVersion);
     result.pushKV("versionHex", strprintf("%08x", blockindex->nVersion));
     result.pushKV("merkleroot", blockindex->hashMerkleRoot.GetHex());
     result.pushKV("time", int64_t(blockindex->nTime));
     result.pushKV("mediantime", int64_t(blockindex->GetMedianTimePast()));
     result.pushKV("nonce", uint64_t(blockindex->nNonce));
     result.pushKV("bits", strprintf("%08x", blockindex->nBits));
     result.pushKV("difficulty", GetDifficulty(blockindex));
     result.pushKV("chainwork", blockindex->nChainWork.GetHex());
     result.pushKV("nTx", uint64_t(blockindex->nTx));
 
     if (blockindex->pprev) {
         result.pushKV("previousblockhash",
                       blockindex->pprev->GetBlockHash().GetHex());
     }
     if (pnext) {
         result.pushKV("nextblockhash", pnext->GetBlockHash().GetHex());
     }
     return result;
 }
 
 UniValue blockToJSON(const CBlock &block, const CBlockIndex *tip,
                      const CBlockIndex *blockindex, bool txDetails) {
     // Serialize passed information without accessing chain state of the active
     // chain!
     // For performance reasons
     AssertLockNotHeld(cs_main);
 
     UniValue result(UniValue::VOBJ);
     result.pushKV("hash", blockindex->GetBlockHash().GetHex());
     const CBlockIndex *pnext;
     int confirmations = ComputeNextBlockAndDepth(tip, blockindex, pnext);
     result.pushKV("confirmations", confirmations);
     result.pushKV("size", (int)::GetSerializeSize(block, PROTOCOL_VERSION));
     result.pushKV("height", blockindex->nHeight);
     result.pushKV("version", block.nVersion);
     result.pushKV("versionHex", strprintf("%08x", block.nVersion));
     result.pushKV("merkleroot", block.hashMerkleRoot.GetHex());
     UniValue txs(UniValue::VARR);
     for (const auto &tx : block.vtx) {
         if (txDetails) {
             UniValue objTx(UniValue::VOBJ);
             TxToUniv(*tx, uint256(), objTx, true, RPCSerializationFlags());
             txs.push_back(objTx);
         } else {
             txs.push_back(tx->GetId().GetHex());
         }
     }
     result.pushKV("tx", txs);
     result.pushKV("time", block.GetBlockTime());
     result.pushKV("mediantime", int64_t(blockindex->GetMedianTimePast()));
     result.pushKV("nonce", uint64_t(block.nNonce));
     result.pushKV("bits", strprintf("%08x", block.nBits));
     result.pushKV("difficulty", GetDifficulty(blockindex));
     result.pushKV("chainwork", blockindex->nChainWork.GetHex());
     result.pushKV("nTx", uint64_t(blockindex->nTx));
 
     if (blockindex->pprev) {
         result.pushKV("previousblockhash",
                       blockindex->pprev->GetBlockHash().GetHex());
     }
     if (pnext) {
         result.pushKV("nextblockhash", pnext->GetBlockHash().GetHex());
     }
     return result;
 }
 
 static RPCHelpMan getblockcount() {
     return RPCHelpMan{
         "getblockcount",
         "Returns the height of the most-work fully-validated chain.\n"
         "The genesis block has height 0.\n",
         {},
         RPCResult{RPCResult::Type::NUM, "", "The current block count"},
         RPCExamples{HelpExampleCli("getblockcount", "") +
                     HelpExampleRpc("getblockcount", "")},
         [&](const RPCHelpMan &self, const Config &config,
             const JSONRPCRequest &request) -> UniValue {
             LOCK(cs_main);
             return ::ChainActive().Height();
         },
     };
 }
 
 static RPCHelpMan getbestblockhash() {
     return RPCHelpMan{
         "getbestblockhash",
         "Returns the hash of the best (tip) block in the "
         "most-work fully-validated chain.\n",
         {},
         RPCResult{RPCResult::Type::STR_HEX, "", "the block hash, hex-encoded"},
         RPCExamples{HelpExampleCli("getbestblockhash", "") +
                     HelpExampleRpc("getbestblockhash", "")},
         [&](const RPCHelpMan &self, const Config &config,
             const JSONRPCRequest &request) -> UniValue {
             LOCK(cs_main);
             return ::ChainActive().Tip()->GetBlockHash().GetHex();
         },
     };
 }
 
 RPCHelpMan getfinalizedblockhash() {
     return RPCHelpMan{
         "getfinalizedblockhash",
         "Returns the hash of the currently finalized block\n",
         {},
         RPCResult{RPCResult::Type::STR_HEX, "", "the block hash, hex-encoded"},
         RPCExamples{HelpExampleCli("getfinalizedblockhash", "") +
                     HelpExampleRpc("getfinalizedblockhash", "")},
         [&](const RPCHelpMan &self, const Config &config,
             const JSONRPCRequest &request) -> UniValue {
             LOCK(cs_main);
             const CBlockIndex *blockIndexFinalized =
                 ::ChainstateActive().GetFinalizedBlock();
             if (blockIndexFinalized) {
                 return blockIndexFinalized->GetBlockHash().GetHex();
             }
             return UniValue(UniValue::VSTR);
         },
     };
 }
 
 void RPCNotifyBlockChange(const CBlockIndex *pindex) {
     if (pindex) {
         LOCK(cs_blockchange);
         latestblock.hash = pindex->GetBlockHash();
         latestblock.height = pindex->nHeight;
     }
     cond_blockchange.notify_all();
 }
 
 static RPCHelpMan waitfornewblock() {
     return RPCHelpMan{
         "waitfornewblock",
         "Waits for a specific new block and returns useful info about it.\n"
         "\nReturns the current block on timeout or exit.\n",
         {
             {"timeout", RPCArg::Type::NUM, /* default */ "0",
              "Time in milliseconds to wait for a response. 0 indicates no "
              "timeout."},
         },
         RPCResult{RPCResult::Type::OBJ,
                   "",
                   "",
                   {
                       {RPCResult::Type::STR_HEX, "hash", "The blockhash"},
                       {RPCResult::Type::NUM, "height", "Block height"},
                   }},
         RPCExamples{HelpExampleCli("waitfornewblock", "1000") +
                     HelpExampleRpc("waitfornewblock", "1000")},
         [&](const RPCHelpMan &self, const Config &config,
             const JSONRPCRequest &request) -> UniValue {
             int timeout = 0;
             if (!request.params[0].isNull()) {
                 timeout = request.params[0].get_int();
             }
 
             CUpdatedBlock block;
             {
                 WAIT_LOCK(cs_blockchange, lock);
                 block = latestblock;
                 if (timeout) {
                     cond_blockchange.wait_for(
                         lock, std::chrono::milliseconds(timeout),
                         [&block]() EXCLUSIVE_LOCKS_REQUIRED(cs_blockchange) {
                             return latestblock.height != block.height ||
                                    latestblock.hash != block.hash ||
                                    !IsRPCRunning();
                         });
                 } else {
                     cond_blockchange.wait(
                         lock,
                         [&block]() EXCLUSIVE_LOCKS_REQUIRED(cs_blockchange) {
                             return latestblock.height != block.height ||
                                    latestblock.hash != block.hash ||
                                    !IsRPCRunning();
                         });
                 }
                 block = latestblock;
             }
             UniValue ret(UniValue::VOBJ);
             ret.pushKV("hash", block.hash.GetHex());
             ret.pushKV("height", block.height);
             return ret;
         },
     };
 }
 
 static RPCHelpMan waitforblock() {
     return RPCHelpMan{
         "waitforblock",
         "Waits for a specific new block and returns useful info about it.\n"
         "\nReturns the current block on timeout or exit.\n",
         {
             {"blockhash", RPCArg::Type::STR_HEX, RPCArg::Optional::NO,
              "Block hash to wait for."},
             {"timeout", RPCArg::Type::NUM, /* default */ "0",
              "Time in milliseconds to wait for a response. 0 indicates no "
              "timeout."},
         },
         RPCResult{RPCResult::Type::OBJ,
                   "",
                   "",
                   {
                       {RPCResult::Type::STR_HEX, "hash", "The blockhash"},
                       {RPCResult::Type::NUM, "height", "Block height"},
                   }},
         RPCExamples{HelpExampleCli("waitforblock",
                                    "\"0000000000079f8ef3d2c688c244eb7a4570b24c9"
                                    "ed7b4a8c619eb02596f8862\" 1000") +
                     HelpExampleRpc("waitforblock",
                                    "\"0000000000079f8ef3d2c688c244eb7a4570b24c9"
                                    "ed7b4a8c619eb02596f8862\", 1000")},
         [&](const RPCHelpMan &self, const Config &config,
             const JSONRPCRequest &request) -> UniValue {
             int timeout = 0;
 
             BlockHash hash(ParseHashV(request.params[0], "blockhash"));
 
             if (!request.params[1].isNull()) {
                 timeout = request.params[1].get_int();
             }
 
             CUpdatedBlock block;
             {
                 WAIT_LOCK(cs_blockchange, lock);
                 if (timeout) {
                     cond_blockchange.wait_for(
                         lock, std::chrono::milliseconds(timeout),
                         [&hash]() EXCLUSIVE_LOCKS_REQUIRED(cs_blockchange) {
                             return latestblock.hash == hash || !IsRPCRunning();
                         });
                 } else {
                     cond_blockchange.wait(
                         lock,
                         [&hash]() EXCLUSIVE_LOCKS_REQUIRED(cs_blockchange) {
                             return latestblock.hash == hash || !IsRPCRunning();
                         });
                 }
                 block = latestblock;
             }
 
             UniValue ret(UniValue::VOBJ);
             ret.pushKV("hash", block.hash.GetHex());
             ret.pushKV("height", block.height);
             return ret;
         },
     };
 }
 
 static RPCHelpMan waitforblockheight() {
     return RPCHelpMan{
         "waitforblockheight",
         "Waits for (at least) block height and returns the height and "
         "hash\nof the current tip.\n"
         "\nReturns the current block on timeout or exit.\n",
         {
             {"height", RPCArg::Type::NUM, RPCArg::Optional::NO,
              "Block height to wait for."},
             {"timeout", RPCArg::Type::NUM, /* default */ "0",
              "Time in milliseconds to wait for a response. 0 indicates no "
              "timeout."},
         },
         RPCResult{RPCResult::Type::OBJ,
                   "",
                   "",
                   {
                       {RPCResult::Type::STR_HEX, "hash", "The blockhash"},
                       {RPCResult::Type::NUM, "height", "Block height"},
                   }},
         RPCExamples{HelpExampleCli("waitforblockheight", "100 1000") +
                     HelpExampleRpc("waitforblockheight", "100, 1000")},
         [&](const RPCHelpMan &self, const Config &config,
             const JSONRPCRequest &request) -> UniValue {
             int timeout = 0;
 
             int height = request.params[0].get_int();
 
             if (!request.params[1].isNull()) {
                 timeout = request.params[1].get_int();
             }
 
             CUpdatedBlock block;
             {
                 WAIT_LOCK(cs_blockchange, lock);
                 if (timeout) {
                     cond_blockchange.wait_for(
                         lock, std::chrono::milliseconds(timeout),
                         [&height]() EXCLUSIVE_LOCKS_REQUIRED(cs_blockchange) {
                             return latestblock.height >= height ||
                                    !IsRPCRunning();
                         });
                 } else {
                     cond_blockchange.wait(
                         lock,
                         [&height]() EXCLUSIVE_LOCKS_REQUIRED(cs_blockchange) {
                             return latestblock.height >= height ||
                                    !IsRPCRunning();
                         });
                 }
                 block = latestblock;
             }
             UniValue ret(UniValue::VOBJ);
             ret.pushKV("hash", block.hash.GetHex());
             ret.pushKV("height", block.height);
             return ret;
         },
     };
 }
 
 static RPCHelpMan syncwithvalidationinterfacequeue() {
     return RPCHelpMan{
         "syncwithvalidationinterfacequeue",
         "Waits for the validation interface queue to catch up on everything "
         "that was there when we entered this function.\n",
         {},
         RPCResult{RPCResult::Type::NONE, "", ""},
         RPCExamples{HelpExampleCli("syncwithvalidationinterfacequeue", "") +
                     HelpExampleRpc("syncwithvalidationinterfacequeue", "")},
         [&](const RPCHelpMan &self, const Config &config,
             const JSONRPCRequest &request) -> UniValue {
             SyncWithValidationInterfaceQueue();
             return NullUniValue;
         },
     };
 }
 
 static RPCHelpMan getdifficulty() {
     return RPCHelpMan{
         "getdifficulty",
         "Returns the proof-of-work difficulty as a multiple of the minimum "
         "difficulty.\n",
         {},
         RPCResult{RPCResult::Type::NUM, "",
                   "the proof-of-work difficulty as a multiple of the minimum "
                   "difficulty."},
         RPCExamples{HelpExampleCli("getdifficulty", "") +
                     HelpExampleRpc("getdifficulty", "")},
         [&](const RPCHelpMan &self, const Config &config,
             const JSONRPCRequest &request) -> UniValue {
             LOCK(cs_main);
             return GetDifficulty(::ChainActive().Tip());
         },
     };
 }
 
 static std::vector<RPCResult> MempoolEntryDescription() {
     const auto &ticker = Currency::get().ticker;
     return {
         RPCResult{RPCResult::Type::NUM, "size", "transaction size."},
         RPCResult{RPCResult::Type::STR_AMOUNT, "fee",
                   "transaction fee in " + ticker + " (DEPRECATED)"},
         RPCResult{RPCResult::Type::STR_AMOUNT, "modifiedfee",
                   "transaction fee with fee deltas used for mining priority "
                   "(DEPRECATED)"},
         RPCResult{RPCResult::Type::NUM_TIME, "time",
                   "local time transaction entered pool in seconds since 1 Jan "
                   "1970 GMT"},
         RPCResult{RPCResult::Type::NUM, "height",
                   "block height when transaction entered pool"},
         RPCResult{RPCResult::Type::NUM, "descendantcount",
                   "number of in-mempool descendant transactions (including "
                   "this one)"},
         RPCResult{RPCResult::Type::NUM, "descendantsize",
                   "transaction size of in-mempool descendants "
                   "(including this one)"},
         RPCResult{RPCResult::Type::STR_AMOUNT, "descendantfees",
                   "modified fees (see above) of in-mempool descendants "
                   "(including this one) (DEPRECATED)"},
         RPCResult{
             RPCResult::Type::NUM, "ancestorcount",
             "number of in-mempool ancestor transactions (including this one)"},
         RPCResult{
             RPCResult::Type::NUM, "ancestorsize",
             "transaction size of in-mempool ancestors (including this one)"},
         RPCResult{RPCResult::Type::STR_AMOUNT, "ancestorfees",
                   "modified fees (see above) of in-mempool ancestors "
                   "(including this one) (DEPRECATED)"},
         RPCResult{RPCResult::Type::OBJ,
                   "fees",
                   "",
                   {
                       RPCResult{RPCResult::Type::STR_AMOUNT, "base",
                                 "transaction fee in " + ticker},
                       RPCResult{RPCResult::Type::STR_AMOUNT, "modified",
                                 "transaction fee with fee deltas used for "
                                 "mining priority in " +
                                     ticker},
                       RPCResult{RPCResult::Type::STR_AMOUNT, "ancestor",
                                 "modified fees (see above) of in-mempool "
                                 "ancestors (including this one) in " +
                                     ticker},
                       RPCResult{RPCResult::Type::STR_AMOUNT, "descendant",
                                 "modified fees (see above) of in-mempool "
                                 "descendants (including this one) in " +
                                     ticker},
                   }},
         RPCResult{
             RPCResult::Type::ARR,
             "depends",
             "unconfirmed transactions used as inputs for this transaction",
             {RPCResult{RPCResult::Type::STR_HEX, "transactionid",
                        "parent transaction id"}}},
         RPCResult{
             RPCResult::Type::ARR,
             "spentby",
             "unconfirmed transactions spending outputs from this transaction",
             {RPCResult{RPCResult::Type::STR_HEX, "transactionid",
                        "child transaction id"}}},
         RPCResult{RPCResult::Type::BOOL, "unbroadcast",
                   "Whether this transaction is currently unbroadcast (initial "
                   "broadcast not yet acknowledged by any peers)"},
     };
 }
 
 static void entryToJSON(const CTxMemPool &pool, UniValue &info,
                         const CTxMemPoolEntry &e)
     EXCLUSIVE_LOCKS_REQUIRED(pool.cs) {
     AssertLockHeld(pool.cs);
 
     UniValue fees(UniValue::VOBJ);
     fees.pushKV("base", e.GetFee());
     fees.pushKV("modified", e.GetModifiedFee());
     fees.pushKV("ancestor", e.GetModFeesWithAncestors());
     fees.pushKV("descendant", e.GetModFeesWithDescendants());
     info.pushKV("fees", fees);
 
     info.pushKV("size", (int)e.GetTxSize());
     info.pushKV("fee", e.GetFee());
     info.pushKV("modifiedfee", e.GetModifiedFee());
     info.pushKV("time", count_seconds(e.GetTime()));
     info.pushKV("height", (int)e.GetHeight());
     info.pushKV("descendantcount", e.GetCountWithDescendants());
     info.pushKV("descendantsize", e.GetSizeWithDescendants());
     info.pushKV("descendantfees", e.GetModFeesWithDescendants() / SATOSHI);
     info.pushKV("ancestorcount", e.GetCountWithAncestors());
     info.pushKV("ancestorsize", e.GetSizeWithAncestors());
     info.pushKV("ancestorfees", e.GetModFeesWithAncestors() / SATOSHI);
     const CTransaction &tx = e.GetTx();
     std::set<std::string> setDepends;
     for (const CTxIn &txin : tx.vin) {
         if (pool.exists(txin.prevout.GetTxId())) {
             setDepends.insert(txin.prevout.GetTxId().ToString());
         }
     }
 
     UniValue depends(UniValue::VARR);
     for (const std::string &dep : setDepends) {
         depends.push_back(dep);
     }
 
     info.pushKV("depends", depends);
 
     UniValue spent(UniValue::VARR);
     const CTxMemPool::txiter &it = pool.mapTx.find(tx.GetId());
     const CTxMemPoolEntry::Children &children = it->GetMemPoolChildrenConst();
     for (const CTxMemPoolEntry &child : children) {
         spent.push_back(child.GetTx().GetId().ToString());
     }
 
     info.pushKV("spentby", spent);
     info.pushKV("unbroadcast", pool.IsUnbroadcastTx(tx.GetId()));
 }
 
-UniValue MempoolToJSON(const CTxMemPool &pool, bool verbose) {
+UniValue MempoolToJSON(const CTxMemPool &pool, bool verbose,
+                       bool include_mempool_sequence) {
     if (verbose) {
+        if (include_mempool_sequence) {
+            throw JSONRPCError(
+                RPC_INVALID_PARAMETER,
+                "Verbose results cannot contain mempool sequence values.");
+        }
         LOCK(pool.cs);
         UniValue o(UniValue::VOBJ);
         for (const CTxMemPoolEntry &e : pool.mapTx) {
             const uint256 &txid = e.GetTx().GetId();
             UniValue info(UniValue::VOBJ);
             entryToJSON(pool, info, e);
             // Mempool has unique entries so there is no advantage in using
             // UniValue::pushKV, which checks if the key already exists in O(N).
             // UniValue::__pushKV is used instead which currently is O(1).
             o.__pushKV(txid.ToString(), info);
         }
         return o;
     } else {
+        uint64_t mempool_sequence;
         std::vector<uint256> vtxids;
-        pool.queryHashes(vtxids);
-
+        {
+            LOCK(pool.cs);
+            pool.queryHashes(vtxids);
+            mempool_sequence = pool.GetSequence();
+        }
         UniValue a(UniValue::VARR);
         for (const uint256 &txid : vtxids) {
             a.push_back(txid.ToString());
         }
 
-        return a;
+        if (!include_mempool_sequence) {
+            return a;
+        } else {
+            UniValue o(UniValue::VOBJ);
+            o.pushKV("txids", a);
+            o.pushKV("mempool_sequence", mempool_sequence);
+            return o;
+        }
     }
 }
 
 static RPCHelpMan getrawmempool() {
     return RPCHelpMan{
         "getrawmempool",
         "Returns all transaction ids in memory pool as a json array of "
         "string transaction ids.\n"
         "\nHint: use getmempoolentry to fetch a specific transaction from the "
         "mempool.\n",
         {
             {"verbose", RPCArg::Type::BOOL, /* default */ "false",
              "True for a json object, false for array of transaction ids"},
+            {"mempool_sequence", RPCArg::Type::BOOL, /* default */ "false",
+             "If verbose=false, returns a json object with transaction list "
+             "and mempool sequence number attached."},
         },
         {
             RPCResult{"for verbose = false",
                       RPCResult::Type::ARR,
                       "",
                       "",
                       {
                           {RPCResult::Type::STR_HEX, "", "The transaction id"},
                       }},
             RPCResult{"for verbose = true",
                       RPCResult::Type::OBJ_DYN,
                       "",
                       "",
                       {
                           {RPCResult::Type::OBJ, "transactionid", "",
                            MempoolEntryDescription()},
                       }},
+            RPCResult{
+                "for verbose = false and mempool_sequence = true",
+                RPCResult::Type::OBJ,
+                "",
+                "",
+                {
+                    {RPCResult::Type::ARR,
+                     "txids",
+                     "",
+                     {
+                         {RPCResult::Type::STR_HEX, "", "The transaction id"},
+                     }},
+                    {RPCResult::Type::NUM, "mempool_sequence",
+                     "The mempool sequence value."},
+                }},
         },
         RPCExamples{HelpExampleCli("getrawmempool", "true") +
                     HelpExampleRpc("getrawmempool", "true")},
         [&](const RPCHelpMan &self, const Config &config,
             const JSONRPCRequest &request) -> UniValue {
             bool fVerbose = false;
             if (!request.params[0].isNull()) {
                 fVerbose = request.params[0].get_bool();
             }
 
-            return MempoolToJSON(EnsureMemPool(request.context), fVerbose);
+            bool include_mempool_sequence = false;
+            if (!request.params[1].isNull()) {
+                include_mempool_sequence = request.params[1].get_bool();
+            }
+
+            return MempoolToJSON(EnsureMemPool(request.context), fVerbose,
+                                 include_mempool_sequence);
         },
     };
 }
 
 static RPCHelpMan getmempoolancestors() {
     return RPCHelpMan{
         "getmempoolancestors",
         "If txid is in the mempool, returns all in-mempool ancestors.\n",
         {
             {"txid", RPCArg::Type::STR_HEX, RPCArg::Optional::NO,
              "The transaction id (must be in mempool)"},
             {"verbose", RPCArg::Type::BOOL, /* default */ "false",
              "True for a json object, false for array of transaction ids"},
         },
         {
             RPCResult{
                 "for verbose = false",
                 RPCResult::Type::ARR,
                 "",
                 "",
                 {{RPCResult::Type::STR_HEX, "",
                   "The transaction id of an in-mempool ancestor transaction"}}},
             RPCResult{"for verbose = true",
                       RPCResult::Type::OBJ_DYN,
                       "",
                       "",
                       {
                           {RPCResult::Type::OBJ, "transactionid", "",
                            MempoolEntryDescription()},
                       }},
         },
         RPCExamples{HelpExampleCli("getmempoolancestors", "\"mytxid\"") +
                     HelpExampleRpc("getmempoolancestors", "\"mytxid\"")},
         [&](const RPCHelpMan &self, const Config &config,
             const JSONRPCRequest &request) -> UniValue {
             bool fVerbose = false;
             if (!request.params[1].isNull()) {
                 fVerbose = request.params[1].get_bool();
             }
 
             TxId txid(ParseHashV(request.params[0], "parameter 1"));
 
             const CTxMemPool &mempool = EnsureMemPool(request.context);
             LOCK(mempool.cs);
 
             CTxMemPool::txiter it = mempool.mapTx.find(txid);
             if (it == mempool.mapTx.end()) {
                 throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY,
                                    "Transaction not in mempool");
             }
 
             CTxMemPool::setEntries setAncestors;
             uint64_t noLimit = std::numeric_limits<uint64_t>::max();
             std::string dummy;
             mempool.CalculateMemPoolAncestors(*it, setAncestors, noLimit,
                                               noLimit, noLimit, noLimit, dummy,
                                               false);
 
             if (!fVerbose) {
                 UniValue o(UniValue::VARR);
                 for (CTxMemPool::txiter ancestorIt : setAncestors) {
                     o.push_back(ancestorIt->GetTx().GetId().ToString());
                 }
                 return o;
             } else {
                 UniValue o(UniValue::VOBJ);
                 for (CTxMemPool::txiter ancestorIt : setAncestors) {
                     const CTxMemPoolEntry &e = *ancestorIt;
                     const TxId &_txid = e.GetTx().GetId();
                     UniValue info(UniValue::VOBJ);
                     entryToJSON(mempool, info, e);
                     o.pushKV(_txid.ToString(), info);
                 }
                 return o;
             }
         },
     };
 }
 
 static RPCHelpMan getmempooldescendants() {
     return RPCHelpMan{
         "getmempooldescendants",
         "If txid is in the mempool, returns all in-mempool descendants.\n",
         {
             {"txid", RPCArg::Type::STR_HEX, RPCArg::Optional::NO,
              "The transaction id (must be in mempool)"},
             {"verbose", RPCArg::Type::BOOL, /* default */ "false",
              "True for a json object, false for array of transaction ids"},
         },
         {
             RPCResult{"for verbose = false",
                       RPCResult::Type::ARR,
                       "",
                       "",
                       {{RPCResult::Type::STR_HEX, "",
                         "The transaction id of an in-mempool descendant "
                         "transaction"}}},
             RPCResult{"for verbose = true",
                       RPCResult::Type::OBJ_DYN,
                       "",
                       "",
                       {
                           {RPCResult::Type::OBJ, "transactionid", "",
                            MempoolEntryDescription()},
                       }},
         },
         RPCExamples{HelpExampleCli("getmempooldescendants", "\"mytxid\"") +
                     HelpExampleRpc("getmempooldescendants", "\"mytxid\"")},
         [&](const RPCHelpMan &self, const Config &config,
             const JSONRPCRequest &request) -> UniValue {
             bool fVerbose = false;
             if (!request.params[1].isNull()) {
                 fVerbose = request.params[1].get_bool();
             }
 
             TxId txid(ParseHashV(request.params[0], "parameter 1"));
 
             const CTxMemPool &mempool = EnsureMemPool(request.context);
             LOCK(mempool.cs);
 
             CTxMemPool::txiter it = mempool.mapTx.find(txid);
             if (it == mempool.mapTx.end()) {
                 throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY,
                                    "Transaction not in mempool");
             }
 
             CTxMemPool::setEntries setDescendants;
             mempool.CalculateDescendants(it, setDescendants);
             // CTxMemPool::CalculateDescendants will include the given tx
             setDescendants.erase(it);
 
             if (!fVerbose) {
                 UniValue o(UniValue::VARR);
                 for (CTxMemPool::txiter descendantIt : setDescendants) {
                     o.push_back(descendantIt->GetTx().GetId().ToString());
                 }
 
                 return o;
             } else {
                 UniValue o(UniValue::VOBJ);
                 for (CTxMemPool::txiter descendantIt : setDescendants) {
                     const CTxMemPoolEntry &e = *descendantIt;
                     const TxId &_txid = e.GetTx().GetId();
                     UniValue info(UniValue::VOBJ);
                     entryToJSON(mempool, info, e);
                     o.pushKV(_txid.ToString(), info);
                 }
                 return o;
             }
         },
     };
 }
 
 static RPCHelpMan getmempoolentry() {
     return RPCHelpMan{
         "getmempoolentry",
         "Returns mempool data for given transaction\n",
         {
             {"txid", RPCArg::Type::STR_HEX, RPCArg::Optional::NO,
              "The transaction id (must be in mempool)"},
         },
         RPCResult{RPCResult::Type::OBJ, "", "", MempoolEntryDescription()},
         RPCExamples{HelpExampleCli("getmempoolentry", "\"mytxid\"") +
                     HelpExampleRpc("getmempoolentry", "\"mytxid\"")},
         [&](const RPCHelpMan &self, const Config &config,
             const JSONRPCRequest &request) -> UniValue {
             TxId txid(ParseHashV(request.params[0], "parameter 1"));
 
             const CTxMemPool &mempool = EnsureMemPool(request.context);
             LOCK(mempool.cs);
 
             CTxMemPool::txiter it = mempool.mapTx.find(txid);
             if (it == mempool.mapTx.end()) {
                 throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY,
                                    "Transaction not in mempool");
             }
 
             const CTxMemPoolEntry &e = *it;
             UniValue info(UniValue::VOBJ);
             entryToJSON(mempool, info, e);
             return info;
         },
     };
 }
 
 static RPCHelpMan getblockhash() {
     return RPCHelpMan{
         "getblockhash",
         "Returns hash of block in best-block-chain at height provided.\n",
         {
             {"height", RPCArg::Type::NUM, RPCArg::Optional::NO,
              "The height index"},
         },
         RPCResult{RPCResult::Type::STR_HEX, "", "The block hash"},
         RPCExamples{HelpExampleCli("getblockhash", "1000") +
                     HelpExampleRpc("getblockhash", "1000")},
         [&](const RPCHelpMan &self, const Config &config,
             const JSONRPCRequest &request) -> UniValue {
             LOCK(cs_main);
 
             int nHeight = request.params[0].get_int();
             if (nHeight < 0 || nHeight > ::ChainActive().Height()) {
                 throw JSONRPCError(RPC_INVALID_PARAMETER,
                                    "Block height out of range");
             }
 
             CBlockIndex *pblockindex = ::ChainActive()[nHeight];
             return pblockindex->GetBlockHash().GetHex();
         },
     };
 }
 
 static RPCHelpMan getblockheader() {
     return RPCHelpMan{
         "getblockheader",
         "If verbose is false, returns a string that is serialized, hex-encoded "
         "data for blockheader 'hash'.\n"
         "If verbose is true, returns an Object with information about "
         "blockheader <hash>.\n",
         {
             {"blockhash", RPCArg::Type::STR_HEX, RPCArg::Optional::NO,
              "The block hash"},
             {"verbose", RPCArg::Type::BOOL, /* default */ "true",
              "true for a json object, false for the hex-encoded data"},
         },
         {
             RPCResult{
                 "for verbose = true",
                 RPCResult::Type::OBJ,
                 "",
                 "",
                 {
                     {RPCResult::Type::STR_HEX, "hash",
                      "the block hash (same as provided)"},
                     {RPCResult::Type::NUM, "confirmations",
                      "The number of confirmations, or -1 if the block is not "
                      "on the main chain"},
                     {RPCResult::Type::NUM, "height",
                      "The block height or index"},
                     {RPCResult::Type::NUM, "version", "The block version"},
                     {RPCResult::Type::STR_HEX, "versionHex",
                      "The block version formatted in hexadecimal"},
                     {RPCResult::Type::STR_HEX, "merkleroot", "The merkle root"},
                     {RPCResult::Type::NUM_TIME, "time",
                      "The block time expressed in " + UNIX_EPOCH_TIME},
                     {RPCResult::Type::NUM_TIME, "mediantime",
                      "The median block time expressed in " + UNIX_EPOCH_TIME},
                     {RPCResult::Type::NUM, "nonce", "The nonce"},
                     {RPCResult::Type::STR_HEX, "bits", "The bits"},
                     {RPCResult::Type::NUM, "difficulty", "The difficulty"},
                     {RPCResult::Type::STR_HEX, "chainwork",
                      "Expected number of hashes required to produce the "
                      "current chain"},
                     {RPCResult::Type::NUM, "nTx",
                      "The number of transactions in the block"},
                     {RPCResult::Type::STR_HEX, "previousblockhash",
                      "The hash of the previous block"},
                     {RPCResult::Type::STR_HEX, "nextblockhash",
                      "The hash of the next block"},
                 }},
             RPCResult{"for verbose=false", RPCResult::Type::STR_HEX, "",
                       "A string that is serialized, hex-encoded data for block "
                       "'hash'"},
         },
         RPCExamples{HelpExampleCli("getblockheader",
                                    "\"00000000c937983704a73af28acdec37b049d214a"
                                    "dbda81d7e2a3dd146f6ed09\"") +
                     HelpExampleRpc("getblockheader",
                                    "\"00000000c937983704a73af28acdec37b049d214a"
                                    "dbda81d7e2a3dd146f6ed09\"")},
         [&](const RPCHelpMan &self, const Config &config,
             const JSONRPCRequest &request) -> UniValue {
             BlockHash hash(ParseHashV(request.params[0], "hash"));
 
             bool fVerbose = true;
             if (!request.params[1].isNull()) {
                 fVerbose = request.params[1].get_bool();
             }
 
             const CBlockIndex *pblockindex;
             const CBlockIndex *tip;
             {
                 LOCK(cs_main);
                 pblockindex = LookupBlockIndex(hash);
                 tip = ::ChainActive().Tip();
             }
 
             if (!pblockindex) {
                 throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY,
                                    "Block not found");
             }
 
             if (!fVerbose) {
                 CDataStream ssBlock(SER_NETWORK, PROTOCOL_VERSION);
                 ssBlock << pblockindex->GetBlockHeader();
                 std::string strHex = HexStr(ssBlock);
                 return strHex;
             }
 
             return blockheaderToJSON(tip, pblockindex);
         },
     };
 }
 
 static CBlock GetBlockChecked(const Config &config,
                               const CBlockIndex *pblockindex) {
     CBlock block;
     if (IsBlockPruned(pblockindex)) {
         throw JSONRPCError(RPC_MISC_ERROR, "Block not available (pruned data)");
     }
 
     if (!ReadBlockFromDisk(block, pblockindex,
                            config.GetChainParams().GetConsensus())) {
         // Block not found on disk. This could be because we have the block
         // header in our index but not yet have the block or did not accept the
         // block.
         throw JSONRPCError(RPC_MISC_ERROR, "Block not found on disk");
     }
 
     return block;
 }
 
 static CBlockUndo GetUndoChecked(const CBlockIndex *pblockindex) {
     CBlockUndo blockUndo;
     if (IsBlockPruned(pblockindex)) {
         throw JSONRPCError(RPC_MISC_ERROR,
                            "Undo data not available (pruned data)");
     }
 
     if (!UndoReadFromDisk(blockUndo, pblockindex)) {
         throw JSONRPCError(RPC_MISC_ERROR, "Can't read undo data from disk");
     }
 
     return blockUndo;
 }
 
 static RPCHelpMan getblock() {
     return RPCHelpMan{
         "getblock",
         "If verbosity is 0 or false, returns a string that is serialized, "
         "hex-encoded data for block 'hash'.\n"
         "If verbosity is 1 or true, returns an Object with information about "
         "block <hash>.\n"
         "If verbosity is 2, returns an Object with information about block "
         "<hash> and information about each transaction.\n",
         {
             {"blockhash", RPCArg::Type::STR_HEX, RPCArg::Optional::NO,
              "The block hash"},
             {"verbosity|verbose", RPCArg::Type::NUM, /* default */ "1",
              "0 for hex-encoded data, 1 for a json object, and 2 for json "
              "object with transaction data"},
         },
         {
             RPCResult{"for verbosity = 0", RPCResult::Type::STR_HEX, "",
                       "A string that is serialized, hex-encoded data for block "
                       "'hash'"},
             RPCResult{
                 "for verbosity = 1",
                 RPCResult::Type::OBJ,
                 "",
                 "",
                 {
                     {RPCResult::Type::STR_HEX, "hash",
                      "the block hash (same as provided)"},
                     {RPCResult::Type::NUM, "confirmations",
                      "The number of confirmations, or -1 if the block is not "
                      "on the main chain"},
                     {RPCResult::Type::NUM, "size", "The block size"},
                     {RPCResult::Type::NUM, "height",
                      "The block height or index"},
                     {RPCResult::Type::NUM, "version", "The block version"},
                     {RPCResult::Type::STR_HEX, "versionHex",
                      "The block version formatted in hexadecimal"},
                     {RPCResult::Type::STR_HEX, "merkleroot", "The merkle root"},
                     {RPCResult::Type::ARR,
                      "tx",
                      "The transaction ids",
                      {{RPCResult::Type::STR_HEX, "", "The transaction id"}}},
                     {RPCResult::Type::NUM_TIME, "time",
                      "The block time expressed in " + UNIX_EPOCH_TIME},
                     {RPCResult::Type::NUM_TIME, "mediantime",
                      "The median block time expressed in " + UNIX_EPOCH_TIME},
                     {RPCResult::Type::NUM, "nonce", "The nonce"},
                     {RPCResult::Type::STR_HEX, "bits", "The bits"},
                     {RPCResult::Type::NUM, "difficulty", "The difficulty"},
                     {RPCResult::Type::STR_HEX, "chainwork",
                      "Expected number of hashes required to produce the chain "
                      "up to this block (in hex)"},
                     {RPCResult::Type::NUM, "nTx",
                      "The number of transactions in the block"},
                     {RPCResult::Type::STR_HEX, "previousblockhash",
                      "The hash of the previous block"},
                     {RPCResult::Type::STR_HEX, "nextblockhash",
                      "The hash of the next block"},
                 }},
             RPCResult{"for verbosity = 2",
                       RPCResult::Type::OBJ,
                       "",
                       "",
                       {
                           {RPCResult::Type::ELISION, "",
                            "Same output as verbosity = 1"},
                           {RPCResult::Type::ARR,
                            "tx",
                            "",
                            {
                                {RPCResult::Type::OBJ,
                                 "",
                                 "",
                                 {
                                     {RPCResult::Type::ELISION, "",
                                      "The transactions in the format of the "
                                      "getrawtransaction RPC. Different from "
                                      "verbosity = 1 \"tx\" result"},
                                 }},
                            }},
                           {RPCResult::Type::ELISION, "",
                            "Same output as verbosity = 1"},
                       }},
         },
         RPCExamples{
             HelpExampleCli("getblock", "\"00000000c937983704a73af28acdec37b049d"
                                        "214adbda81d7e2a3dd146f6ed09\"") +
             HelpExampleRpc("getblock", "\"00000000c937983704a73af28acdec37b049d"
                                        "214adbda81d7e2a3dd146f6ed09\"")},
         [&](const RPCHelpMan &self, const Config &config,
             const JSONRPCRequest &request) -> UniValue {
             BlockHash hash(ParseHashV(request.params[0], "blockhash"));
 
             int verbosity = 1;
             if (!request.params[1].isNull()) {
                 if (request.params[1].isNum()) {
                     verbosity = request.params[1].get_int();
                 } else {
                     verbosity = request.params[1].get_bool() ? 1 : 0;
                 }
             }
 
             CBlock block;
             const CBlockIndex *pblockindex;
             const CBlockIndex *tip;
             {
                 LOCK(cs_main);
                 pblockindex = LookupBlockIndex(hash);
                 tip = ::ChainActive().Tip();
 
                 if (!pblockindex) {
                     throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY,
                                        "Block not found");
                 }
 
                 block = GetBlockChecked(config, pblockindex);
             }
 
             if (verbosity <= 0) {
                 CDataStream ssBlock(SER_NETWORK,
                                     PROTOCOL_VERSION | RPCSerializationFlags());
                 ssBlock << block;
                 std::string strHex = HexStr(ssBlock);
                 return strHex;
             }
 
             return blockToJSON(block, tip, pblockindex, verbosity >= 2);
         },
     };
 }
 
 static RPCHelpMan pruneblockchain() {
     return RPCHelpMan{
         "pruneblockchain",
         "",
         {
             {"height", RPCArg::Type::NUM, RPCArg::Optional::NO,
              "The block height to prune up to. May be set to a discrete "
              "height, or to a " +
                  UNIX_EPOCH_TIME +
                  "\n"
                  "                  to prune blocks whose block time is at "
                  "least 2 hours older than the provided timestamp."},
         },
         RPCResult{RPCResult::Type::NUM, "", "Height of the last block pruned"},
         RPCExamples{HelpExampleCli("pruneblockchain", "1000") +
                     HelpExampleRpc("pruneblockchain", "1000")},
         [&](const RPCHelpMan &self, const Config &config,
             const JSONRPCRequest &request) -> UniValue {
             if (!fPruneMode) {
                 throw JSONRPCError(
                     RPC_MISC_ERROR,
                     "Cannot prune blocks because node is not in prune mode.");
             }
 
             LOCK(cs_main);
 
             int heightParam = request.params[0].get_int();
             if (heightParam < 0) {
                 throw JSONRPCError(RPC_INVALID_PARAMETER,
                                    "Negative block height.");
             }
 
             // Height value more than a billion is too high to be a block
             // height, and too low to be a block time (corresponds to timestamp
             // from Sep 2001).
             if (heightParam > 1000000000) {
                 // Add a 2 hour buffer to include blocks which might have had
                 // old timestamps
                 CBlockIndex *pindex = ::ChainActive().FindEarliestAtLeast(
                     heightParam - TIMESTAMP_WINDOW, 0);
                 if (!pindex) {
                     throw JSONRPCError(RPC_INVALID_PARAMETER,
                                        "Could not find block with at least the "
                                        "specified timestamp.");
                 }
                 heightParam = pindex->nHeight;
             }
 
             unsigned int height = (unsigned int)heightParam;
             unsigned int chainHeight = (unsigned int)::ChainActive().Height();
             if (chainHeight < config.GetChainParams().PruneAfterHeight()) {
                 throw JSONRPCError(RPC_MISC_ERROR,
                                    "Blockchain is too short for pruning.");
             } else if (height > chainHeight) {
                 throw JSONRPCError(
                     RPC_INVALID_PARAMETER,
                     "Blockchain is shorter than the attempted prune height.");
             } else if (height > chainHeight - MIN_BLOCKS_TO_KEEP) {
                 LogPrint(BCLog::RPC,
                          "Attempt to prune blocks close to the tip. "
                          "Retaining the minimum number of blocks.\n");
                 height = chainHeight - MIN_BLOCKS_TO_KEEP;
             }
 
             PruneBlockFilesManual(height);
             const CBlockIndex *block = ::ChainActive().Tip();
             CHECK_NONFATAL(block);
             while (block->pprev && (block->pprev->nStatus.hasData())) {
                 block = block->pprev;
             }
             return uint64_t(block->nHeight);
         },
     };
 }
 
 static RPCHelpMan gettxoutsetinfo() {
     return RPCHelpMan{
         "gettxoutsetinfo",
         "Returns statistics about the unspent transaction output set.\n"
         "Note this call may take some time.\n",
         {
             {"hash_type", RPCArg::Type::STR, /* default */ "hash_serialized",
              "Which UTXO set hash should be calculated. Options: "
              "'hash_serialized' (the legacy algorithm), 'none'."},
         },
         RPCResult{RPCResult::Type::OBJ,
                   "",
                   "",
                   {
                       {RPCResult::Type::NUM, "height",
                        "The current block height (index)"},
                       {RPCResult::Type::STR_HEX, "bestblock",
                        "The hash of the block at the tip of the chain"},
                       {RPCResult::Type::NUM, "transactions",
                        "The number of transactions with unspent outputs"},
                       {RPCResult::Type::NUM, "txouts",
                        "The number of unspent transaction outputs"},
                       {RPCResult::Type::NUM, "bogosize",
                        "A meaningless metric for UTXO set size"},
                       {RPCResult::Type::STR_HEX, "hash_serialized",
                        "The serialized hash (only present if 'hash_serialized' "
                        "hash_type is chosen)"},
                       {RPCResult::Type::NUM, "disk_size",
                        "The estimated size of the chainstate on disk"},
                       {RPCResult::Type::STR_AMOUNT, "total_amount",
                        "The total amount"},
                   }},
         RPCExamples{HelpExampleCli("gettxoutsetinfo", "") +
                     HelpExampleRpc("gettxoutsetinfo", "")},
         [&](const RPCHelpMan &self, const Config &config,
             const JSONRPCRequest &request) -> UniValue {
             UniValue ret(UniValue::VOBJ);
 
             CCoinsStats stats;
             ::ChainstateActive().ForceFlushStateToDisk();
 
             const CoinStatsHashType hash_type = ParseHashType(
                 request.params[0], CoinStatsHashType::HASH_SERIALIZED);
 
             CCoinsView *coins_view =
                 WITH_LOCK(cs_main, return &ChainstateActive().CoinsDB());
             NodeContext &node = EnsureNodeContext(request.context);
             if (GetUTXOStats(coins_view, stats, hash_type,
                              node.rpc_interruption_point)) {
                 ret.pushKV("height", int64_t(stats.nHeight));
                 ret.pushKV("bestblock", stats.hashBlock.GetHex());
                 ret.pushKV("transactions", int64_t(stats.nTransactions));
                 ret.pushKV("txouts", int64_t(stats.nTransactionOutputs));
                 ret.pushKV("bogosize", int64_t(stats.nBogoSize));
                 if (hash_type == CoinStatsHashType::HASH_SERIALIZED) {
                     ret.pushKV("hash_serialized",
                                stats.hashSerialized.GetHex());
                 }
                 ret.pushKV("disk_size", stats.nDiskSize);
                 ret.pushKV("total_amount", stats.nTotalAmount);
             } else {
                 throw JSONRPCError(RPC_INTERNAL_ERROR,
                                    "Unable to read UTXO set");
             }
             return ret;
         },
     };
 }
 
 RPCHelpMan gettxout() {
     return RPCHelpMan{
         "gettxout",
         "Returns details about an unspent transaction output.\n",
         {
             {"txid", RPCArg::Type::STR_HEX, RPCArg::Optional::NO,
              "The transaction id"},
             {"n", RPCArg::Type::NUM, RPCArg::Optional::NO, "vout number"},
             {"include_mempool", RPCArg::Type::BOOL, /* default */ "true",
              "Whether to include the mempool. Note that an unspent output that "
              "is spent in the mempool won't appear."},
         },
         RPCResult{
             RPCResult::Type::OBJ,
             "",
             "",
             {
                 {RPCResult::Type::STR_HEX, "bestblock",
                  "The hash of the block at the tip of the chain"},
                 {RPCResult::Type::NUM, "confirmations",
                  "The number of confirmations"},
                 {RPCResult::Type::STR_AMOUNT, "value",
                  "The transaction value in " + Currency::get().ticker},
                 {RPCResult::Type::OBJ,
                  "scriptPubKey",
                  "",
                  {
                      {RPCResult::Type::STR_HEX, "asm", ""},
                      {RPCResult::Type::STR_HEX, "hex", ""},
                      {RPCResult::Type::NUM, "reqSigs",
                       "Number of required signatures"},
                      {RPCResult::Type::STR_HEX, "type",
                       "The type, eg pubkeyhash"},
                      {RPCResult::Type::ARR,
                       "addresses",
                       "array of bitcoin addresses",
                       {{RPCResult::Type::STR, "address", "bitcoin address"}}},
                  }},
                 {RPCResult::Type::BOOL, "coinbase", "Coinbase or not"},
             }},
         RPCExamples{"\nGet unspent transactions\n" +
                     HelpExampleCli("listunspent", "") + "\nView the details\n" +
                     HelpExampleCli("gettxout", "\"txid\" 1") +
                     "\nAs a JSON-RPC call\n" +
                     HelpExampleRpc("gettxout", "\"txid\", 1")},
         [&](const RPCHelpMan &self, const Config &config,
             const JSONRPCRequest &request) -> UniValue {
             LOCK(cs_main);
 
             UniValue ret(UniValue::VOBJ);
 
             TxId txid(ParseHashV(request.params[0], "txid"));
             int n = request.params[1].get_int();
             COutPoint out(txid, n);
             bool fMempool = true;
             if (!request.params[2].isNull()) {
                 fMempool = request.params[2].get_bool();
             }
 
             Coin coin;
             CCoinsViewCache *coins_view = &::ChainstateActive().CoinsTip();
 
             if (fMempool) {
                 const CTxMemPool &mempool = EnsureMemPool(request.context);
                 LOCK(mempool.cs);
                 CCoinsViewMemPool view(coins_view, mempool);
                 if (!view.GetCoin(out, coin) || mempool.isSpent(out)) {
                     return NullUniValue;
                 }
             } else {
                 if (!coins_view->GetCoin(out, coin)) {
                     return NullUniValue;
                 }
             }
 
             const CBlockIndex *pindex =
                 LookupBlockIndex(coins_view->GetBestBlock());
             ret.pushKV("bestblock", pindex->GetBlockHash().GetHex());
             if (coin.GetHeight() == MEMPOOL_HEIGHT) {
                 ret.pushKV("confirmations", 0);
             } else {
                 ret.pushKV("confirmations",
                            int64_t(pindex->nHeight - coin.GetHeight() + 1));
             }
             ret.pushKV("value", coin.GetTxOut().nValue);
             UniValue o(UniValue::VOBJ);
             ScriptPubKeyToUniv(coin.GetTxOut().scriptPubKey, o, true);
             ret.pushKV("scriptPubKey", o);
             ret.pushKV("coinbase", coin.IsCoinBase());
 
             return ret;
         },
     };
 }
 
 static RPCHelpMan verifychain() {
     return RPCHelpMan{
         "verifychain",
         "Verifies blockchain database.\n",
         {
             {"checklevel", RPCArg::Type::NUM,
              /* default */ strprintf("%d, range=0-4", DEFAULT_CHECKLEVEL),
              strprintf("How thorough the block verification is:\n - %s",
                        Join(CHECKLEVEL_DOC, "\n- "))},
             {"nblocks", RPCArg::Type::NUM,
              /* default */ strprintf("%d, 0=all", DEFAULT_CHECKBLOCKS),
              "The number of blocks to check."},
         },
         RPCResult{RPCResult::Type::BOOL, "", "Verified or not"},
         RPCExamples{HelpExampleCli("verifychain", "") +
                     HelpExampleRpc("verifychain", "")},
         [&](const RPCHelpMan &self, const Config &config,
             const JSONRPCRequest &request) -> UniValue {
             const int check_level(request.params[0].isNull()
                                       ? DEFAULT_CHECKLEVEL
                                       : request.params[0].get_int());
             const int check_depth{request.params[1].isNull()
                                       ? DEFAULT_CHECKBLOCKS
                                       : request.params[1].get_int()};
 
             LOCK(cs_main);
 
             return CVerifyDB().VerifyDB(config,
                                         &::ChainstateActive().CoinsTip(),
                                         check_level, check_depth);
         },
     };
 }
 
 static void BIP9SoftForkDescPushBack(UniValue &softforks,
                                      const Consensus::Params &consensusParams,
                                      Consensus::DeploymentPos id)
     EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
     // For BIP9 deployments.
     // Deployments (e.g. testdummy) with timeout value before Jan 1, 2009 are
     // hidden. A timeout value of 0 guarantees a softfork will never be
     // activated. This is used when merging logic to implement a proposed
     // softfork without a specified deployment schedule.
     if (consensusParams.vDeployments[id].nTimeout <= 1230768000) {
         return;
     }
 
     UniValue bip9(UniValue::VOBJ);
     const ThresholdState thresholdState =
         VersionBitsTipState(consensusParams, id);
     switch (thresholdState) {
         case ThresholdState::DEFINED:
             bip9.pushKV("status", "defined");
             break;
         case ThresholdState::STARTED:
             bip9.pushKV("status", "started");
             break;
         case ThresholdState::LOCKED_IN:
             bip9.pushKV("status", "locked_in");
             break;
         case ThresholdState::ACTIVE:
             bip9.pushKV("status", "active");
             break;
         case ThresholdState::FAILED:
             bip9.pushKV("status", "failed");
             break;
     }
     if (ThresholdState::STARTED == thresholdState) {
         bip9.pushKV("bit", consensusParams.vDeployments[id].bit);
     }
     bip9.pushKV("start_time", consensusParams.vDeployments[id].nStartTime);
     bip9.pushKV("timeout", consensusParams.vDeployments[id].nTimeout);
     int64_t since_height = VersionBitsTipStateSinceHeight(consensusParams, id);
     bip9.pushKV("since", since_height);
     if (ThresholdState::STARTED == thresholdState) {
         UniValue statsUV(UniValue::VOBJ);
         BIP9Stats statsStruct = VersionBitsTipStatistics(consensusParams, id);
         statsUV.pushKV("period", statsStruct.period);
         statsUV.pushKV("threshold", statsStruct.threshold);
         statsUV.pushKV("elapsed", statsStruct.elapsed);
         statsUV.pushKV("count", statsStruct.count);
         statsUV.pushKV("possible", statsStruct.possible);
         bip9.pushKV("statistics", statsUV);
     }
 
     UniValue rv(UniValue::VOBJ);
     rv.pushKV("type", "bip9");
     rv.pushKV("bip9", bip9);
     if (ThresholdState::ACTIVE == thresholdState) {
         rv.pushKV("height", since_height);
     }
     rv.pushKV("active", ThresholdState::ACTIVE == thresholdState);
 
     softforks.pushKV(VersionBitsDeploymentInfo[id].name, rv);
 }
 
 RPCHelpMan getblockchaininfo() {
     return RPCHelpMan{
         "getblockchaininfo",
         "Returns an object containing various state info regarding blockchain "
         "processing.\n",
         {},
         RPCResult{
             RPCResult::Type::OBJ,
             "",
             "",
             {
                 {RPCResult::Type::STR, "chain",
                  "current network name (main, test, regtest)"},
                 {RPCResult::Type::NUM, "blocks",
                  "the height of the most-work fully-validated chain. The "
                  "genesis block has height 0"},
                 {RPCResult::Type::NUM, "headers",
                  "the current number of headers we have validated"},
                 {RPCResult::Type::STR, "bestblockhash",
                  "the hash of the currently best block"},
                 {RPCResult::Type::NUM, "difficulty", "the current difficulty"},
                 {RPCResult::Type::NUM, "mediantime",
                  "median time for the current best block"},
                 {RPCResult::Type::NUM, "verificationprogress",
                  "estimate of verification progress [0..1]"},
                 {RPCResult::Type::BOOL, "initialblockdownload",
                  "(debug information) estimate of whether this node is in "
                  "Initial Block Download mode"},
                 {RPCResult::Type::STR_HEX, "chainwork",
                  "total amount of work in active chain, in hexadecimal"},
                 {RPCResult::Type::NUM, "size_on_disk",
                  "the estimated size of the block and undo files on disk"},
                 {RPCResult::Type::BOOL, "pruned",
                  "if the blocks are subject to pruning"},
                 {RPCResult::Type::NUM, "pruneheight",
                  "lowest-height complete block stored (only present if pruning "
                  "is enabled)"},
                 {RPCResult::Type::BOOL, "automatic_pruning",
                  "whether automatic pruning is enabled (only present if "
                  "pruning is enabled)"},
                 {RPCResult::Type::NUM, "prune_target_size",
                  "the target size used by pruning (only present if automatic "
                  "pruning is enabled)"},
                 {RPCResult::Type::OBJ_DYN,
                  "softforks",
                  "status of softforks",
                  {
                      {RPCResult::Type::OBJ,
                       "xxxx",
                       "name of the softfork",
                       {
                           {RPCResult::Type::STR, "type",
                            "one of \"buried\", \"bip9\""},
                           {RPCResult::Type::OBJ,
                            "bip9",
                            "status of bip9 softforks (only for \"bip9\" type)",
                            {
                                {RPCResult::Type::STR, "status",
                                 "one of \"defined\", \"started\", "
                                 "\"locked_in\", \"active\", \"failed\""},
                                {RPCResult::Type::NUM, "bit",
                                 "the bit (0-28) in the block version field "
                                 "used to signal this softfork (only for "
                                 "\"started\" status)"},
                                {RPCResult::Type::NUM_TIME, "start_time",
                                 "the minimum median time past of a block at "
                                 "which the bit gains its meaning"},
                                {RPCResult::Type::NUM_TIME, "timeout",
                                 "the median time past of a block at which the "
                                 "deployment is considered failed if not yet "
                                 "locked in"},
                                {RPCResult::Type::NUM, "since",
                                 "height of the first block to which the status "
                                 "applies"},
                                {RPCResult::Type::OBJ,
                                 "statistics",
                                 "numeric statistics about BIP9 signalling for "
                                 "a softfork",
                                 {
                                     {RPCResult::Type::NUM, "period",
                                      "the length in blocks of the BIP9 "
                                      "signalling period"},
                                     {RPCResult::Type::NUM, "threshold",
                                      "the number of blocks with the version "
                                      "bit set required to activate the "
                                      "feature"},
                                     {RPCResult::Type::NUM, "elapsed",
                                      "the number of blocks elapsed since the "
                                      "beginning of the current period"},
                                     {RPCResult::Type::NUM, "count",
                                      "the number of blocks with the version "
                                      "bit set in the current period"},
                                     {RPCResult::Type::BOOL, "possible",
                                      "returns false if there are not enough "
                                      "blocks left in this period to pass "
                                      "activation threshold"},
                                 }},
                            }},
                           {RPCResult::Type::NUM, "height",
                            "height of the first block which the rules are or "
                            "will be enforced (only for \"buried\" type, or "
                            "\"bip9\" type with \"active\" status)"},
                           {RPCResult::Type::BOOL, "active",
                            "true if the rules are enforced for the mempool and "
                            "the next block"},
                       }},
                  }},
                 {RPCResult::Type::STR, "warnings",
                  "any network and blockchain warnings"},
             }},
         RPCExamples{HelpExampleCli("getblockchaininfo", "") +
                     HelpExampleRpc("getblockchaininfo", "")},
         [&](const RPCHelpMan &self, const Config &config,
             const JSONRPCRequest &request) -> UniValue {
             LOCK(cs_main);
 
             const CChainParams &chainparams = config.GetChainParams();
 
             const CBlockIndex *tip = ::ChainActive().Tip();
             UniValue obj(UniValue::VOBJ);
             obj.pushKV("chain", chainparams.NetworkIDString());
             obj.pushKV("blocks", int(::ChainActive().Height()));
             obj.pushKV("headers",
                        pindexBestHeader ? pindexBestHeader->nHeight : -1);
             obj.pushKV("bestblockhash", tip->GetBlockHash().GetHex());
             obj.pushKV("difficulty", double(GetDifficulty(tip)));
             obj.pushKV("mediantime", int64_t(tip->GetMedianTimePast()));
             obj.pushKV("verificationprogress",
                        GuessVerificationProgress(Params().TxData(), tip));
             obj.pushKV("initialblockdownload",
                        ::ChainstateActive().IsInitialBlockDownload());
             obj.pushKV("chainwork", tip->nChainWork.GetHex());
             obj.pushKV("size_on_disk", CalculateCurrentUsage());
             obj.pushKV("pruned", fPruneMode);
 
             if (fPruneMode) {
                 const CBlockIndex *block = tip;
                 CHECK_NONFATAL(block);
                 while (block->pprev && (block->pprev->nStatus.hasData())) {
                     block = block->pprev;
                 }
 
                 obj.pushKV("pruneheight", block->nHeight);
 
                 // if 0, execution bypasses the whole if block.
                 bool automatic_pruning = (gArgs.GetArg("-prune", 0) != 1);
                 obj.pushKV("automatic_pruning", automatic_pruning);
                 if (automatic_pruning) {
                     obj.pushKV("prune_target_size", nPruneTarget);
                 }
             }
 
             UniValue softforks(UniValue::VOBJ);
             for (int i = 0; i < (int)Consensus::MAX_VERSION_BITS_DEPLOYMENTS;
                  i++) {
                 BIP9SoftForkDescPushBack(softforks, chainparams.GetConsensus(),
                                          Consensus::DeploymentPos(i));
             }
             obj.pushKV("softforks", softforks);
 
             obj.pushKV("warnings", GetWarnings(false).original);
             return obj;
         },
     };
 }
 
 /** Comparison function for sorting the getchaintips heads.  */
 struct CompareBlocksByHeight {
     bool operator()(const CBlockIndex *a, const CBlockIndex *b) const {
         // Make sure that unequal blocks with the same height do not compare
         // equal. Use the pointers themselves to make a distinction.
         if (a->nHeight != b->nHeight) {
             return (a->nHeight > b->nHeight);
         }
 
         return a < b;
     }
 };
 
 static RPCHelpMan getchaintips() {
     return RPCHelpMan{
         "getchaintips",
         "Return information about all known tips in the block tree, including "
         "the main chain as well as orphaned branches.\n",
         {},
         RPCResult{
             RPCResult::Type::ARR,
             "",
             "",
             {{RPCResult::Type::OBJ,
               "",
               "",
               {
                   {RPCResult::Type::NUM, "height", "height of the chain tip"},
                   {RPCResult::Type::STR_HEX, "hash", "block hash of the tip"},
                   {RPCResult::Type::NUM, "branchlen",
                    "zero for main chain, otherwise length of branch connecting "
                    "the tip to the main chain"},
                   {RPCResult::Type::STR, "status",
                    "status of the chain, \"active\" for the main chain\n"
                    "Possible values for status:\n"
                    "1.  \"invalid\"               This branch contains at "
                    "least one invalid block\n"
                    "2.  \"parked\"                This branch contains at "
                    "least one parked block\n"
                    "3.  \"headers-only\"          Not all blocks for this "
                    "branch are available, but the headers are valid\n"
                    "4.  \"valid-headers\"         All blocks are available for "
                    "this branch, but they were never fully validated\n"
                    "5.  \"valid-fork\"            This branch is not part of "
                    "the active chain, but is fully validated\n"
                    "6.  \"active\"                This is the tip of the "
                    "active main chain, which is certainly valid"},
               }}}},
         RPCExamples{HelpExampleCli("getchaintips", "") +
                     HelpExampleRpc("getchaintips", "")},
         [&](const RPCHelpMan &self, const Config &config,
             const JSONRPCRequest &request) -> UniValue {
             ChainstateManager &chainman = EnsureChainman(request.context);
             LOCK(cs_main);
 
             /**
              * Idea: The set of chain tips is the active chain tip, plus orphan
              * blocks which do not have another orphan building off of them.
              * Algorithm:
              *  - Make one pass through BlockIndex(), picking out the orphan
              * blocks, and also storing a set of the orphan block's pprev
              * pointers.
              *  - Iterate through the orphan blocks. If the block isn't pointed
              * to by another orphan, it is a chain tip.
              *  - Add the active chain tip
              */
             std::set<const CBlockIndex *, CompareBlocksByHeight> setTips;
             std::set<const CBlockIndex *> setOrphans;
             std::set<const CBlockIndex *> setPrevs;
 
             for (const std::pair<const BlockHash, CBlockIndex *> &item :
                  chainman.BlockIndex()) {
                 if (!chainman.ActiveChain().Contains(item.second)) {
                     setOrphans.insert(item.second);
                     setPrevs.insert(item.second->pprev);
                 }
             }
 
             for (std::set<const CBlockIndex *>::iterator it =
                      setOrphans.begin();
                  it != setOrphans.end(); ++it) {
                 if (setPrevs.erase(*it) == 0) {
                     setTips.insert(*it);
                 }
             }
 
             // Always report the currently active tip.
             setTips.insert(chainman.ActiveChain().Tip());
 
             /* Construct the output array.  */
             UniValue res(UniValue::VARR);
             for (const CBlockIndex *block : setTips) {
                 UniValue obj(UniValue::VOBJ);
                 obj.pushKV("height", block->nHeight);
                 obj.pushKV("hash", block->phashBlock->GetHex());
 
                 const int branchLen =
                     block->nHeight -
                     chainman.ActiveChain().FindFork(block)->nHeight;
                 obj.pushKV("branchlen", branchLen);
 
                 std::string status;
                 if (chainman.ActiveChain().Contains(block)) {
                     // This block is part of the currently active chain.
                     status = "active";
                 } else if (block->nStatus.isInvalid()) {
                     // This block or one of its ancestors is invalid.
                     status = "invalid";
                 } else if (block->nStatus.isOnParkedChain()) {
                     // This block or one of its ancestors is parked.
                     status = "parked";
                 } else if (!block->HaveTxsDownloaded()) {
                     // This block cannot be connected because full block data
                     // for it or one of its parents is missing.
                     status = "headers-only";
                 } else if (block->IsValid(BlockValidity::SCRIPTS)) {
                     // This block is fully validated, but no longer part of the
                     // active chain. It was probably the active block once, but
                     // was reorganized.
                     status = "valid-fork";
                 } else if (block->IsValid(BlockValidity::TREE)) {
                     // The headers for this block are valid, but it has not been
                     // validated. It was probably never part of the most-work
                     // chain.
                     status = "valid-headers";
                 } else {
                     // No clue.
                     status = "unknown";
                 }
                 obj.pushKV("status", status);
 
                 res.push_back(obj);
             }
 
             return res;
         },
     };
 }
 
 UniValue MempoolInfoToJSON(const CTxMemPool &pool) {
     // Make sure this call is atomic in the pool.
     LOCK(pool.cs);
     UniValue ret(UniValue::VOBJ);
     ret.pushKV("loaded", pool.IsLoaded());
     ret.pushKV("size", (int64_t)pool.size());
     ret.pushKV("bytes", (int64_t)pool.GetTotalTxSize());
     ret.pushKV("usage", (int64_t)pool.DynamicMemoryUsage());
     size_t maxmempool =
         gArgs.GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000;
     ret.pushKV("maxmempool", (int64_t)maxmempool);
     ret.pushKV(
         "mempoolminfee",
         std::max(pool.GetMinFee(maxmempool), ::minRelayTxFee).GetFeePerK());
     ret.pushKV("minrelaytxfee", ::minRelayTxFee.GetFeePerK());
     ret.pushKV("unbroadcastcount", uint64_t{pool.GetUnbroadcastTxs().size()});
     return ret;
 }
 
 static RPCHelpMan getmempoolinfo() {
     return RPCHelpMan{
         "getmempoolinfo",
         "Returns details on the active state of the TX memory pool.\n",
         {},
         RPCResult{
             RPCResult::Type::OBJ,
             "",
             "",
             {
                 {RPCResult::Type::BOOL, "loaded",
                  "True if the mempool is fully loaded"},
                 {RPCResult::Type::NUM, "size", "Current tx count"},
                 {RPCResult::Type::NUM, "bytes", "Sum of all transaction sizes"},
                 {RPCResult::Type::NUM, "usage",
                  "Total memory usage for the mempool"},
                 {RPCResult::Type::NUM, "maxmempool",
                  "Maximum memory usage for the mempool"},
                 {RPCResult::Type::STR_AMOUNT, "mempoolminfee",
                  "Minimum fee rate in " + Currency::get().ticker +
                      "/kB for tx to be accepted. Is the maximum of "
                      "minrelaytxfee and minimum mempool fee"},
                 {RPCResult::Type::STR_AMOUNT, "minrelaytxfee",
                  "Current minimum relay fee for transactions"},
                 {RPCResult::Type::NUM, "unbroadcastcount",
                  "Current number of transactions that haven't passed initial "
                  "broadcast yet"},
             }},
         RPCExamples{HelpExampleCli("getmempoolinfo", "") +
                     HelpExampleRpc("getmempoolinfo", "")},
         [&](const RPCHelpMan &self, const Config &config,
             const JSONRPCRequest &request) -> UniValue {
             return MempoolInfoToJSON(EnsureMemPool(request.context));
         },
     };
 }
 
 static RPCHelpMan preciousblock() {
     return RPCHelpMan{
         "preciousblock",
         "Treats a block as if it were received before others with the same "
         "work.\n"
         "\nA later preciousblock call can override the effect of an earlier "
         "one.\n"
         "\nThe effects of preciousblock are not retained across restarts.\n",
         {
             {"blockhash", RPCArg::Type::STR_HEX, RPCArg::Optional::NO,
              "the hash of the block to mark as precious"},
         },
         RPCResult{RPCResult::Type::NONE, "", ""},
         RPCExamples{HelpExampleCli("preciousblock", "\"blockhash\"") +
                     HelpExampleRpc("preciousblock", "\"blockhash\"")},
         [&](const RPCHelpMan &self, const Config &config,
             const JSONRPCRequest &request) -> UniValue {
             BlockHash hash(ParseHashV(request.params[0], "blockhash"));
             CBlockIndex *pblockindex;
 
             {
                 LOCK(cs_main);
                 pblockindex = LookupBlockIndex(hash);
                 if (!pblockindex) {
                     throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY,
                                        "Block not found");
                 }
             }
 
             BlockValidationState state;
             PreciousBlock(config, state, pblockindex);
 
             if (!state.IsValid()) {
                 throw JSONRPCError(RPC_DATABASE_ERROR, state.GetRejectReason());
             }
 
             return NullUniValue;
         },
     };
 }
 
 RPCHelpMan finalizeblock() {
     return RPCHelpMan{
         "finalizeblock",
         "Treats a block as final. It cannot be reorged. Any chain\n"
         "that does not contain this block is invalid. Used on a less\n"
         "work chain, it can effectively PUT YOU OUT OF CONSENSUS.\n"
         "USE WITH CAUTION!\n",
         {
             {"blockhash", RPCArg::Type::STR_HEX, RPCArg::Optional::NO,
              "the hash of the block to mark as invalid"},
         },
         RPCResult{RPCResult::Type::NONE, "", ""},
         RPCExamples{HelpExampleCli("finalizeblock", "\"blockhash\"") +
                     HelpExampleRpc("finalizeblock", "\"blockhash\"")},
         [&](const RPCHelpMan &self, const Config &config,
             const JSONRPCRequest &request) -> UniValue {
             std::string strHash = request.params[0].get_str();
             BlockHash hash(uint256S(strHash));
             BlockValidationState state;
 
             CBlockIndex *pblockindex = nullptr;
             {
                 LOCK(cs_main);
                 pblockindex = LookupBlockIndex(hash);
                 if (!pblockindex) {
                     throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY,
                                        "Block not found");
                 }
             } // end of locked cs_main scope
 
             ::ChainstateActive().FinalizeBlock(config, state, pblockindex);
 
             if (state.IsValid()) {
                 ActivateBestChain(config, state);
             }
 
             if (!state.IsValid()) {
                 throw JSONRPCError(RPC_DATABASE_ERROR, state.ToString());
             }
 
             return NullUniValue;
         },
     };
 }
 
 static RPCHelpMan invalidateblock() {
     return RPCHelpMan{
         "invalidateblock",
         "Permanently marks a block as invalid, as if it violated a consensus "
         "rule.\n",
         {
             {"blockhash", RPCArg::Type::STR_HEX, RPCArg::Optional::NO,
              "the hash of the block to mark as invalid"},
         },
         RPCResult{RPCResult::Type::NONE, "", ""},
         RPCExamples{HelpExampleCli("invalidateblock", "\"blockhash\"") +
                     HelpExampleRpc("invalidateblock", "\"blockhash\"")},
         [&](const RPCHelpMan &self, const Config &config,
             const JSONRPCRequest &request) -> UniValue {
             const BlockHash hash(ParseHashV(request.params[0], "blockhash"));
             BlockValidationState state;
 
             CBlockIndex *pblockindex;
             {
                 LOCK(cs_main);
                 pblockindex = LookupBlockIndex(hash);
                 if (!pblockindex) {
                     throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY,
                                        "Block not found");
                 }
             }
             ::ChainstateActive().InvalidateBlock(config, state, pblockindex);
 
             if (state.IsValid()) {
                 ActivateBestChain(config, state);
             }
 
             if (!state.IsValid()) {
                 throw JSONRPCError(RPC_DATABASE_ERROR, state.ToString());
             }
 
             return NullUniValue;
         },
     };
 }
 
 RPCHelpMan parkblock() {
     return RPCHelpMan{
         "parkblock",
         "Marks a block as parked.\n",
         {
             {"blockhash", RPCArg::Type::STR_HEX, RPCArg::Optional::NO,
              "the hash of the block to park"},
         },
         RPCResult{RPCResult::Type::NONE, "", ""},
         RPCExamples{HelpExampleCli("parkblock", "\"blockhash\"") +
                     HelpExampleRpc("parkblock", "\"blockhash\"")},
         [&](const RPCHelpMan &self, const Config &config,
             const JSONRPCRequest &request) -> UniValue {
             const std::string strHash = request.params[0].get_str();
             const BlockHash hash(uint256S(strHash));
             BlockValidationState state;
 
             CBlockIndex *pblockindex = nullptr;
             {
                 LOCK(cs_main);
                 pblockindex = LookupBlockIndex(hash);
                 if (!pblockindex) {
                     throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY,
                                        "Block not found");
                 }
             }
             ::ChainstateActive().ParkBlock(config, state, pblockindex);
 
             if (state.IsValid()) {
                 ActivateBestChain(config, state);
             }
 
             if (!state.IsValid()) {
                 throw JSONRPCError(RPC_DATABASE_ERROR, state.GetRejectReason());
             }
 
             return NullUniValue;
         },
     };
 }
 
 static RPCHelpMan reconsiderblock() {
     return RPCHelpMan{
         "reconsiderblock",
         "Removes invalidity status of a block, its ancestors and its"
         "descendants, reconsider them for activation.\n"
         "This can be used to undo the effects of invalidateblock.\n",
         {
             {"blockhash", RPCArg::Type::STR_HEX, RPCArg::Optional::NO,
              "the hash of the block to reconsider"},
         },
         RPCResult{RPCResult::Type::NONE, "", ""},
         RPCExamples{HelpExampleCli("reconsiderblock", "\"blockhash\"") +
                     HelpExampleRpc("reconsiderblock", "\"blockhash\"")},
         [&](const RPCHelpMan &self, const Config &config,
             const JSONRPCRequest &request) -> UniValue {
             const BlockHash hash(ParseHashV(request.params[0], "blockhash"));
 
             {
                 LOCK(cs_main);
                 CBlockIndex *pblockindex = LookupBlockIndex(hash);
                 if (!pblockindex) {
                     throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY,
                                        "Block not found");
                 }
 
                 ResetBlockFailureFlags(pblockindex);
             }
 
             BlockValidationState state;
             ActivateBestChain(config, state);
 
             if (!state.IsValid()) {
                 throw JSONRPCError(RPC_DATABASE_ERROR, state.ToString());
             }
 
             return NullUniValue;
         },
     };
 }
 
 RPCHelpMan unparkblock() {
     return RPCHelpMan{
         "unparkblock",
         "Removes parked status of a block and its descendants, reconsider "
         "them for activation.\n"
         "This can be used to undo the effects of parkblock.\n",
         {
             {"blockhash", RPCArg::Type::STR_HEX, RPCArg::Optional::NO,
              "the hash of the block to unpark"},
         },
         RPCResult{RPCResult::Type::NONE, "", ""},
         RPCExamples{HelpExampleCli("unparkblock", "\"blockhash\"") +
                     HelpExampleRpc("unparkblock", "\"blockhash\"")},
         [&](const RPCHelpMan &self, const Config &config,
             const JSONRPCRequest &request) -> UniValue {
             const std::string strHash = request.params[0].get_str();
             const BlockHash hash(uint256S(strHash));
 
             {
                 LOCK(cs_main);
 
                 CBlockIndex *pblockindex = LookupBlockIndex(hash);
                 if (!pblockindex) {
                     throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY,
                                        "Block not found");
                 }
 
                 UnparkBlockAndChildren(pblockindex);
             }
 
             BlockValidationState state;
             ActivateBestChain(config, state);
 
             if (!state.IsValid()) {
                 throw JSONRPCError(RPC_DATABASE_ERROR, state.GetRejectReason());
             }
 
             return NullUniValue;
         },
     };
 }
 
 static RPCHelpMan getchaintxstats() {
     return RPCHelpMan{
         "getchaintxstats",
         "Compute statistics about the total number and rate of transactions "
         "in the chain.\n",
         {
             {"nblocks", RPCArg::Type::NUM, /* default */ "one month",
              "Size of the window in number of blocks"},
             {"blockhash", RPCArg::Type::STR_HEX, /* default */ "chain tip",
              "The hash of the block that ends the window."},
         },
         RPCResult{RPCResult::Type::OBJ,
                   "",
                   "",
                   {
                       {RPCResult::Type::NUM_TIME, "time",
                        "The timestamp for the final block in the window, "
                        "expressed in " +
                            UNIX_EPOCH_TIME},
                       {RPCResult::Type::NUM, "txcount",
                        "The total number of transactions in the chain up to "
                        "that point"},
                       {RPCResult::Type::STR_HEX, "window_final_block_hash",
                        "The hash of the final block in the window"},
                       {RPCResult::Type::NUM, "window_final_block_height",
                        "The height of the final block in the window."},
                       {RPCResult::Type::NUM, "window_block_count",
                        "Size of the window in number of blocks"},
                       {RPCResult::Type::NUM, "window_tx_count",
                        "The number of transactions in the window. Only "
                        "returned if \"window_block_count\" is > 0"},
                       {RPCResult::Type::NUM, "window_interval",
                        "The elapsed time in the window in seconds. Only "
                        "returned if \"window_block_count\" is > 0"},
                       {RPCResult::Type::NUM, "txrate",
                        "The average rate of transactions per second in the "
                        "window. Only returned if \"window_interval\" is > 0"},
                   }},
         RPCExamples{HelpExampleCli("getchaintxstats", "") +
                     HelpExampleRpc("getchaintxstats", "2016")},
         [&](const RPCHelpMan &self, const Config &config,
             const JSONRPCRequest &request) -> UniValue {
             const CBlockIndex *pindex;
 
             // By default: 1 month
             int blockcount =
                 30 * 24 * 60 * 60 /
                 config.GetChainParams().GetConsensus().nPowTargetSpacing;
 
             if (request.params[1].isNull()) {
                 LOCK(cs_main);
                 pindex = ::ChainActive().Tip();
             } else {
                 BlockHash hash(ParseHashV(request.params[1], "blockhash"));
                 LOCK(cs_main);
                 pindex = LookupBlockIndex(hash);
                 if (!pindex) {
                     throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY,
                                        "Block not found");
                 }
                 if (!::ChainActive().Contains(pindex)) {
                     throw JSONRPCError(RPC_INVALID_PARAMETER,
                                        "Block is not in main chain");
                 }
             }
 
             CHECK_NONFATAL(pindex != nullptr);
 
             if (request.params[0].isNull()) {
                 blockcount =
                     std::max(0, std::min(blockcount, pindex->nHeight - 1));
             } else {
                 blockcount = request.params[0].get_int();
 
                 if (blockcount < 0 ||
                     (blockcount > 0 && blockcount >= pindex->nHeight)) {
                     throw JSONRPCError(RPC_INVALID_PARAMETER,
                                        "Invalid block count: "
                                        "should be between 0 and "
                                        "the block's height - 1");
                 }
             }
 
             const CBlockIndex *pindexPast =
                 pindex->GetAncestor(pindex->nHeight - blockcount);
             int nTimeDiff =
                 pindex->GetMedianTimePast() - pindexPast->GetMedianTimePast();
             int nTxDiff =
                 pindex->GetChainTxCount() - pindexPast->GetChainTxCount();
 
             UniValue ret(UniValue::VOBJ);
             ret.pushKV("time", pindex->GetBlockTime());
             ret.pushKV("txcount", pindex->GetChainTxCount());
             ret.pushKV("window_final_block_hash",
                        pindex->GetBlockHash().GetHex());
             ret.pushKV("window_final_block_height", pindex->nHeight);
             ret.pushKV("window_block_count", blockcount);
             if (blockcount > 0) {
                 ret.pushKV("window_tx_count", nTxDiff);
                 ret.pushKV("window_interval", nTimeDiff);
                 if (nTimeDiff > 0) {
                     ret.pushKV("txrate", double(nTxDiff) / nTimeDiff);
                 }
             }
 
             return ret;
         },
     };
 }
 
 template <typename T>
 static T CalculateTruncatedMedian(std::vector<T> &scores) {
     size_t size = scores.size();
     if (size == 0) {
         return T();
     }
 
     std::sort(scores.begin(), scores.end());
     if (size % 2 == 0) {
         return (scores[size / 2 - 1] + scores[size / 2]) / 2;
     } else {
         return scores[size / 2];
     }
 }
 
 template <typename T> static inline bool SetHasKeys(const std::set<T> &set) {
     return false;
 }
 template <typename T, typename Tk, typename... Args>
 static inline bool SetHasKeys(const std::set<T> &set, const Tk &key,
                               const Args &... args) {
     return (set.count(key) != 0) || SetHasKeys(set, args...);
 }
 
 // outpoint (needed for the utxo index) + nHeight + fCoinBase
 static constexpr size_t PER_UTXO_OVERHEAD =
     sizeof(COutPoint) + sizeof(uint32_t) + sizeof(bool);
 
 static RPCHelpMan getblockstats() {
     const auto &ticker = Currency::get().ticker;
     return RPCHelpMan{
         "getblockstats",
         "Compute per block statistics for a given window. All amounts are "
         "in " +
             ticker +
             ".\n"
             "It won't work for some heights with pruning.\n",
         {
             {"hash_or_height",
              RPCArg::Type::NUM,
              RPCArg::Optional::NO,
              "The block hash or height of the target block",
              "",
              {"", "string or numeric"}},
             {"stats",
              RPCArg::Type::ARR,
              /* default */ "all values",
              "Values to plot (see result below)",
              {
                  {"height", RPCArg::Type::STR, RPCArg::Optional::OMITTED,
                   "Selected statistic"},
                  {"time", RPCArg::Type::STR, RPCArg::Optional::OMITTED,
                   "Selected statistic"},
              },
              "stats"},
         },
         RPCResult{
             RPCResult::Type::OBJ,
             "",
             "",
             {
                 {RPCResult::Type::NUM, "avgfee", "Average fee in the block"},
                 {RPCResult::Type::NUM, "avgfeerate",
                  "Average feerate (in satoshis per virtual byte)"},
                 {RPCResult::Type::NUM, "avgtxsize", "Average transaction size"},
                 {RPCResult::Type::STR_HEX, "blockhash",
                  "The block hash (to check for potential reorgs)"},
                 {RPCResult::Type::NUM, "height", "The height of the block"},
                 {RPCResult::Type::NUM, "ins",
                  "The number of inputs (excluding coinbase)"},
                 {RPCResult::Type::NUM, "maxfee", "Maximum fee in the block"},
                 {RPCResult::Type::NUM, "maxfeerate",
                  "Maximum feerate (in satoshis per virtual byte)"},
                 {RPCResult::Type::NUM, "maxtxsize", "Maximum transaction size"},
                 {RPCResult::Type::NUM, "medianfee",
                  "Truncated median fee in the block"},
                 {RPCResult::Type::NUM, "medianfeerate",
                  "Truncated median feerate (in " + ticker + " per byte)"},
                 {RPCResult::Type::NUM, "mediantime",
                  "The block median time past"},
                 {RPCResult::Type::NUM, "mediantxsize",
                  "Truncated median transaction size"},
                 {RPCResult::Type::NUM, "minfee", "Minimum fee in the block"},
                 {RPCResult::Type::NUM, "minfeerate",
                  "Minimum feerate (in satoshis per virtual byte)"},
                 {RPCResult::Type::NUM, "mintxsize", "Minimum transaction size"},
                 {RPCResult::Type::NUM, "outs", "The number of outputs"},
                 {RPCResult::Type::NUM, "subsidy", "The block subsidy"},
                 {RPCResult::Type::NUM, "time", "The block time"},
                 {RPCResult::Type::NUM, "total_out",
                  "Total amount in all outputs (excluding coinbase and thus "
                  "reward [ie subsidy + totalfee])"},
                 {RPCResult::Type::NUM, "total_size",
                  "Total size of all non-coinbase transactions"},
                 {RPCResult::Type::NUM, "totalfee", "The fee total"},
                 {RPCResult::Type::NUM, "txs",
                  "The number of transactions (including coinbase)"},
                 {RPCResult::Type::NUM, "utxo_increase",
                  "The increase/decrease in the number of unspent outputs"},
                 {RPCResult::Type::NUM, "utxo_size_inc",
                  "The increase/decrease in size for the utxo index (not "
                  "discounting op_return and similar)"},
             }},
         RPCExamples{
             HelpExampleCli(
                 "getblockstats",
                 R"('"00000000c937983704a73af28acdec37b049d214adbda81d7e2a3dd146f6ed09"' '["minfeerate","avgfeerate"]')") +
             HelpExampleCli("getblockstats",
                            R"(1000 '["minfeerate","avgfeerate"]')") +
             HelpExampleRpc(
                 "getblockstats",
                 R"("00000000c937983704a73af28acdec37b049d214adbda81d7e2a3dd146f6ed09", ["minfeerate","avgfeerate"])") +
             HelpExampleRpc("getblockstats",
                            R"(1000, ["minfeerate","avgfeerate"])")},
         [&](const RPCHelpMan &self, const Config &config,
             const JSONRPCRequest &request) -> UniValue {
             LOCK(cs_main);
 
             CBlockIndex *pindex;
             if (request.params[0].isNum()) {
                 const int height = request.params[0].get_int();
                 const int current_tip = ::ChainActive().Height();
                 if (height < 0) {
                     throw JSONRPCError(
                         RPC_INVALID_PARAMETER,
                         strprintf("Target block height %d is negative",
                                   height));
                 }
                 if (height > current_tip) {
                     throw JSONRPCError(
                         RPC_INVALID_PARAMETER,
                         strprintf("Target block height %d after current tip %d",
                                   height, current_tip));
                 }
 
                 pindex = ::ChainActive()[height];
             } else {
                 const BlockHash hash(
                     ParseHashV(request.params[0], "hash_or_height"));
                 pindex = LookupBlockIndex(hash);
                 if (!pindex) {
                     throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY,
                                        "Block not found");
                 }
                 if (!::ChainActive().Contains(pindex)) {
                     throw JSONRPCError(RPC_INVALID_PARAMETER,
                                        strprintf("Block is not in chain %s",
                                                  Params().NetworkIDString()));
                 }
             }
 
             CHECK_NONFATAL(pindex != nullptr);
 
             std::set<std::string> stats;
             if (!request.params[1].isNull()) {
                 const UniValue stats_univalue = request.params[1].get_array();
                 for (unsigned int i = 0; i < stats_univalue.size(); i++) {
                     const std::string stat = stats_univalue[i].get_str();
                     stats.insert(stat);
                 }
             }
 
             const CBlock block = GetBlockChecked(config, pindex);
             const CBlockUndo blockUndo = GetUndoChecked(pindex);
 
             // Calculate everything if nothing selected (default)
             const bool do_all = stats.size() == 0;
             const bool do_mediantxsize =
                 do_all || stats.count("mediantxsize") != 0;
             const bool do_medianfee = do_all || stats.count("medianfee") != 0;
             const bool do_medianfeerate =
                 do_all || stats.count("medianfeerate") != 0;
             const bool loop_inputs =
                 do_all || do_medianfee || do_medianfeerate ||
                 SetHasKeys(stats, "utxo_size_inc", "totalfee", "avgfee",
                            "avgfeerate", "minfee", "maxfee", "minfeerate",
                            "maxfeerate");
             const bool loop_outputs =
                 do_all || loop_inputs || stats.count("total_out");
             const bool do_calculate_size =
                 do_mediantxsize || loop_inputs ||
                 SetHasKeys(stats, "total_size", "avgtxsize", "mintxsize",
                            "maxtxsize");
 
             const int64_t blockMaxSize = config.GetMaxBlockSize();
             Amount maxfee = Amount::zero();
             Amount maxfeerate = Amount::zero();
             Amount minfee = MAX_MONEY;
             Amount minfeerate = MAX_MONEY;
             Amount total_out = Amount::zero();
             Amount totalfee = Amount::zero();
             int64_t inputs = 0;
             int64_t maxtxsize = 0;
             int64_t mintxsize = blockMaxSize;
             int64_t outputs = 0;
             int64_t total_size = 0;
             int64_t utxo_size_inc = 0;
             std::vector<Amount> fee_array;
             std::vector<Amount> feerate_array;
             std::vector<int64_t> txsize_array;
 
             for (size_t i = 0; i < block.vtx.size(); ++i) {
                 const auto &tx = block.vtx.at(i);
                 outputs += tx->vout.size();
                 Amount tx_total_out = Amount::zero();
                 if (loop_outputs) {
                     for (const CTxOut &out : tx->vout) {
                         tx_total_out += out.nValue;
                         utxo_size_inc +=
                             GetSerializeSize(out, PROTOCOL_VERSION) +
                             PER_UTXO_OVERHEAD;
                     }
                 }
 
                 if (tx->IsCoinBase()) {
                     continue;
                 }
 
                 // Don't count coinbase's fake input
                 inputs += tx->vin.size();
                 // Don't count coinbase reward
                 total_out += tx_total_out;
 
                 int64_t tx_size = 0;
                 if (do_calculate_size) {
                     tx_size = tx->GetTotalSize();
                     if (do_mediantxsize) {
                         txsize_array.push_back(tx_size);
                     }
                     maxtxsize = std::max(maxtxsize, tx_size);
                     mintxsize = std::min(mintxsize, tx_size);
                     total_size += tx_size;
                 }
 
                 if (loop_inputs) {
                     Amount tx_total_in = Amount::zero();
                     const auto &txundo = blockUndo.vtxundo.at(i - 1);
                     for (const Coin &coin : txundo.vprevout) {
                         const CTxOut &prevoutput = coin.GetTxOut();
 
                         tx_total_in += prevoutput.nValue;
                         utxo_size_inc -=
                             GetSerializeSize(prevoutput, PROTOCOL_VERSION) +
                             PER_UTXO_OVERHEAD;
                     }
 
                     Amount txfee = tx_total_in - tx_total_out;
                     CHECK_NONFATAL(MoneyRange(txfee));
                     if (do_medianfee) {
                         fee_array.push_back(txfee);
                     }
                     maxfee = std::max(maxfee, txfee);
                     minfee = std::min(minfee, txfee);
                     totalfee += txfee;
 
                     Amount feerate = txfee / tx_size;
                     if (do_medianfeerate) {
                         feerate_array.push_back(feerate);
                     }
                     maxfeerate = std::max(maxfeerate, feerate);
                     minfeerate = std::min(minfeerate, feerate);
                 }
             }
 
             UniValue ret_all(UniValue::VOBJ);
             ret_all.pushKV("avgfee",
                            block.vtx.size() > 1
                                ? (totalfee / int((block.vtx.size() - 1)))
                                : Amount::zero());
             ret_all.pushKV("avgfeerate", total_size > 0
                                              ? (totalfee / total_size)
                                              : Amount::zero());
             ret_all.pushKV("avgtxsize",
                            (block.vtx.size() > 1)
                                ? total_size / (block.vtx.size() - 1)
                                : 0);
             ret_all.pushKV("blockhash", pindex->GetBlockHash().GetHex());
             ret_all.pushKV("height", (int64_t)pindex->nHeight);
             ret_all.pushKV("ins", inputs);
             ret_all.pushKV("maxfee", maxfee);
             ret_all.pushKV("maxfeerate", maxfeerate);
             ret_all.pushKV("maxtxsize", maxtxsize);
             ret_all.pushKV("medianfee", CalculateTruncatedMedian(fee_array));
             ret_all.pushKV("medianfeerate",
                            CalculateTruncatedMedian(feerate_array));
             ret_all.pushKV("mediantime", pindex->GetMedianTimePast());
             ret_all.pushKV("mediantxsize",
                            CalculateTruncatedMedian(txsize_array));
             ret_all.pushKV("minfee",
                            minfee == MAX_MONEY ? Amount::zero() : minfee);
             ret_all.pushKV("minfeerate", minfeerate == MAX_MONEY
                                              ? Amount::zero()
                                              : minfeerate);
             ret_all.pushKV("mintxsize",
                            mintxsize == blockMaxSize ? 0 : mintxsize);
             ret_all.pushKV("outs", outputs);
             ret_all.pushKV("subsidy", GetBlockSubsidy(pindex->nHeight,
                                                       Params().GetConsensus()));
             ret_all.pushKV("time", pindex->GetBlockTime());
             ret_all.pushKV("total_out", total_out);
             ret_all.pushKV("total_size", total_size);
             ret_all.pushKV("totalfee", totalfee);
             ret_all.pushKV("txs", (int64_t)block.vtx.size());
             ret_all.pushKV("utxo_increase", outputs - inputs);
             ret_all.pushKV("utxo_size_inc", utxo_size_inc);
 
             if (do_all) {
                 return ret_all;
             }
 
             UniValue ret(UniValue::VOBJ);
             for (const std::string &stat : stats) {
                 const UniValue &value = ret_all[stat];
                 if (value.isNull()) {
                     throw JSONRPCError(
                         RPC_INVALID_PARAMETER,
                         strprintf("Invalid selected statistic %s", stat));
                 }
                 ret.pushKV(stat, value);
             }
             return ret;
         },
     };
 }
 
 static RPCHelpMan savemempool() {
     return RPCHelpMan{
         "savemempool",
         "Dumps the mempool to disk. It will fail until the previous dump is "
         "fully loaded.\n",
         {},
         RPCResult{RPCResult::Type::NONE, "", ""},
         RPCExamples{HelpExampleCli("savemempool", "") +
                     HelpExampleRpc("savemempool", "")},
         [&](const RPCHelpMan &self, const Config &config,
             const JSONRPCRequest &request) -> UniValue {
             const CTxMemPool &mempool = EnsureMemPool(request.context);
 
             if (!mempool.IsLoaded()) {
                 throw JSONRPCError(RPC_MISC_ERROR,
                                    "The mempool was not loaded yet");
             }
 
             if (!DumpMempool(mempool)) {
                 throw JSONRPCError(RPC_MISC_ERROR,
                                    "Unable to dump mempool to disk");
             }
 
             return NullUniValue;
         },
     };
 }
 
 namespace {
 //! Search for a given set of pubkey scripts
 static bool FindScriptPubKey(std::atomic<int> &scan_progress,
                              const std::atomic<bool> &should_abort,
                              int64_t &count, CCoinsViewCursor *cursor,
                              const std::set<CScript> &needles,
                              std::map<COutPoint, Coin> &out_results,
                              std::function<void()> &interruption_point) {
     scan_progress = 0;
     count = 0;
     while (cursor->Valid()) {
         COutPoint key;
         Coin coin;
         if (!cursor->GetKey(key) || !cursor->GetValue(coin)) {
             return false;
         }
         if (++count % 8192 == 0) {
             interruption_point();
             if (should_abort) {
                 // allow to abort the scan via the abort reference
                 return false;
             }
         }
         if (count % 256 == 0) {
             // update progress reference every 256 item
             const TxId &txid = key.GetTxId();
             uint32_t high = 0x100 * *txid.begin() + *(txid.begin() + 1);
             scan_progress = int(high * 100.0 / 65536.0 + 0.5);
         }
         if (needles.count(coin.GetTxOut().scriptPubKey)) {
             out_results.emplace(key, coin);
         }
         cursor->Next();
     }
     scan_progress = 100;
     return true;
 }
 } // namespace
 
 /** RAII object to prevent concurrency issue when scanning the txout set */
 static std::atomic<int> g_scan_progress;
 static std::atomic<bool> g_scan_in_progress;
 static std::atomic<bool> g_should_abort_scan;
 class CoinsViewScanReserver {
 private:
     bool m_could_reserve;
 
 public:
     explicit CoinsViewScanReserver() : m_could_reserve(false) {}
 
     bool reserve() {
         CHECK_NONFATAL(!m_could_reserve);
         if (g_scan_in_progress.exchange(true)) {
             return false;
         }
         m_could_reserve = true;
         return true;
     }
 
     ~CoinsViewScanReserver() {
         if (m_could_reserve) {
             g_scan_in_progress = false;
         }
     }
 };
 
 static RPCHelpMan scantxoutset() {
     const auto &ticker = Currency::get().ticker;
     return RPCHelpMan{
         "scantxoutset",
         "EXPERIMENTAL warning: this call may be removed or changed in future "
         "releases.\n"
         "\nScans the unspent transaction output set for entries that match "
         "certain output descriptors.\n"
         "Examples of output descriptors are:\n"
         "    addr(<address>)                      Outputs whose scriptPubKey "
         "corresponds to the specified address (does not include P2PK)\n"
         "    raw(<hex script>)                    Outputs whose scriptPubKey "
         "equals the specified hex scripts\n"
         "    combo(<pubkey>)                      P2PK and P2PKH outputs for "
         "the given pubkey\n"
         "    pkh(<pubkey>)                        P2PKH outputs for the given "
         "pubkey\n"
         "    sh(multi(<n>,<pubkey>,<pubkey>,...)) P2SH-multisig outputs for "
         "the given threshold and pubkeys\n"
         "\nIn the above, <pubkey> either refers to a fixed public key in "
         "hexadecimal notation, or to an xpub/xprv optionally followed by one\n"
         "or more path elements separated by \"/\", and optionally ending in "
         "\"/*\" (unhardened), or \"/*'\" or \"/*h\" (hardened) to specify all\n"
         "unhardened or hardened child keys.\n"
         "In the latter case, a range needs to be specified by below if "
         "different from 1000.\n"
         "For more information on output descriptors, see the documentation in "
         "the doc/descriptors.md file.\n",
         {
             {"action", RPCArg::Type::STR, RPCArg::Optional::NO,
              "The action to execute\n"
              "                                      \"start\" for starting a "
              "scan\n"
              "                                      \"abort\" for aborting the "
              "current scan (returns true when abort was successful)\n"
              "                                      \"status\" for "
              "progress report (in %) of the current scan"},
             {"scanobjects",
              RPCArg::Type::ARR,
              RPCArg::Optional::OMITTED,
              "Array of scan objects. Required for \"start\" action\n"
              "                                  Every scan object is either a "
              "string descriptor or an object:",
              {
                  {"descriptor", RPCArg::Type::STR, RPCArg::Optional::OMITTED,
                   "An output descriptor"},
                  {
                      "",
                      RPCArg::Type::OBJ,
                      RPCArg::Optional::OMITTED,
                      "An object with output descriptor and metadata",
                      {
                          {"desc", RPCArg::Type::STR, RPCArg::Optional::NO,
                           "An output descriptor"},
                          {"range", RPCArg::Type::RANGE, /* default */ "1000",
                           "The range of HD chain indexes to explore (either "
                           "end or [begin,end])"},
                      },
                  },
              },
              "[scanobjects,...]"},
         },
         RPCResult{
             RPCResult::Type::OBJ,
             "",
             "",
             {
                 {RPCResult::Type::BOOL, "success",
                  "Whether the scan was completed"},
                 {RPCResult::Type::NUM, "txouts",
                  "The number of unspent transaction outputs scanned"},
                 {RPCResult::Type::NUM, "height",
                  "The current block height (index)"},
                 {RPCResult::Type::STR_HEX, "bestblock",
                  "The hash of the block at the tip of the chain"},
                 {RPCResult::Type::ARR,
                  "unspents",
                  "",
                  {
                      {RPCResult::Type::OBJ,
                       "",
                       "",
                       {
                           {RPCResult::Type::STR_HEX, "txid",
                            "The transaction id"},
                           {RPCResult::Type::NUM, "vout", "The vout value"},
                           {RPCResult::Type::STR_HEX, "scriptPubKey",
                            "The script key"},
                           {RPCResult::Type::STR, "desc",
                            "A specialized descriptor for the matched "
                            "scriptPubKey"},
                           {RPCResult::Type::STR_AMOUNT, "amount",
                            "The total amount in " + ticker +
                                " of the unspent output"},
                           {RPCResult::Type::NUM, "height",
                            "Height of the unspent transaction output"},
                       }},
                  }},
                 {RPCResult::Type::STR_AMOUNT, "total_amount",
                  "The total amount of all found unspent outputs in " + ticker},
             }},
         RPCExamples{""},
         [&](const RPCHelpMan &self, const Config &config,
             const JSONRPCRequest &request) -> UniValue {
             RPCTypeCheck(request.params, {UniValue::VSTR, UniValue::VARR});
 
             UniValue result(UniValue::VOBJ);
             if (request.params[0].get_str() == "status") {
                 CoinsViewScanReserver reserver;
                 if (reserver.reserve()) {
                     // no scan in progress
                     return NullUniValue;
                 }
                 result.pushKV("progress", g_scan_progress.load());
                 return result;
             } else if (request.params[0].get_str() == "abort") {
                 CoinsViewScanReserver reserver;
                 if (reserver.reserve()) {
                     // reserve was possible which means no scan was running
                     return false;
                 }
                 // set the abort flag
                 g_should_abort_scan = true;
                 return true;
             } else if (request.params[0].get_str() == "start") {
                 CoinsViewScanReserver reserver;
                 if (!reserver.reserve()) {
                     throw JSONRPCError(RPC_INVALID_PARAMETER,
                                        "Scan already in progress, use action "
                                        "\"abort\" or \"status\"");
                 }
 
                 if (request.params.size() < 2) {
                     throw JSONRPCError(RPC_MISC_ERROR,
                                        "scanobjects argument is required for "
                                        "the start action");
                 }
 
                 std::set<CScript> needles;
                 std::map<CScript, std::string> descriptors;
                 Amount total_in = Amount::zero();
 
                 // loop through the scan objects
                 for (const UniValue &scanobject :
                      request.params[1].get_array().getValues()) {
                     FlatSigningProvider provider;
                     auto scripts =
                         EvalDescriptorStringOrObject(scanobject, provider);
                     for (const auto &script : scripts) {
                         std::string inferred =
                             InferDescriptor(script, provider)->ToString();
                         needles.emplace(script);
                         descriptors.emplace(std::move(script),
                                             std::move(inferred));
                     }
                 }
 
                 // Scan the unspent transaction output set for inputs
                 UniValue unspents(UniValue::VARR);
                 std::vector<CTxOut> input_txos;
                 std::map<COutPoint, Coin> coins;
                 g_should_abort_scan = false;
                 g_scan_progress = 0;
                 int64_t count = 0;
                 std::unique_ptr<CCoinsViewCursor> pcursor;
                 CBlockIndex *tip;
                 {
                     LOCK(cs_main);
                     ::ChainstateActive().ForceFlushStateToDisk();
                     pcursor = std::unique_ptr<CCoinsViewCursor>(
                         ::ChainstateActive().CoinsDB().Cursor());
                     CHECK_NONFATAL(pcursor);
                     tip = ::ChainActive().Tip();
                     CHECK_NONFATAL(tip);
                 }
                 NodeContext &node = EnsureNodeContext(request.context);
                 bool res = FindScriptPubKey(
                     g_scan_progress, g_should_abort_scan, count, pcursor.get(),
                     needles, coins, node.rpc_interruption_point);
                 result.pushKV("success", res);
                 result.pushKV("txouts", count);
                 result.pushKV("height", tip->nHeight);
                 result.pushKV("bestblock", tip->GetBlockHash().GetHex());
 
                 for (const auto &it : coins) {
                     const COutPoint &outpoint = it.first;
                     const Coin &coin = it.second;
                     const CTxOut &txo = coin.GetTxOut();
                     input_txos.push_back(txo);
                     total_in += txo.nValue;
 
                     UniValue unspent(UniValue::VOBJ);
                     unspent.pushKV("txid", outpoint.GetTxId().GetHex());
                     unspent.pushKV("vout", int32_t(outpoint.GetN()));
                     unspent.pushKV("scriptPubKey", HexStr(txo.scriptPubKey));
                     unspent.pushKV("desc", descriptors[txo.scriptPubKey]);
                     unspent.pushKV("amount", txo.nValue);
                     unspent.pushKV("height", int32_t(coin.GetHeight()));
 
                     unspents.push_back(unspent);
                 }
                 result.pushKV("unspents", unspents);
                 result.pushKV("total_amount", total_in);
             } else {
                 throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid command");
             }
             return result;
         },
     };
 }
 
 static RPCHelpMan getblockfilter() {
     return RPCHelpMan{
         "getblockfilter",
         "Retrieve a BIP 157 content filter for a particular block.\n",
         {
             {"blockhash", RPCArg::Type::STR_HEX, RPCArg::Optional::NO,
              "The hash of the block"},
             {"filtertype", RPCArg::Type::STR, /*default*/ "basic",
              "The type name of the filter"},
         },
         RPCResult{RPCResult::Type::OBJ,
                   "",
                   "",
                   {
                       {RPCResult::Type::STR_HEX, "filter",
                        "the hex-encoded filter data"},
                       {RPCResult::Type::STR_HEX, "header",
                        "the hex-encoded filter header"},
                   }},
         RPCExamples{
             HelpExampleCli("getblockfilter",
                            "\"00000000c937983704a73af28acdec37b049d214a"
                            "dbda81d7e2a3dd146f6ed09\" \"basic\"") +
             HelpExampleRpc("getblockfilter",
                            "\"00000000c937983704a73af28acdec37b049d214adbda81d7"
                            "e2a3dd146f6ed09\", \"basic\"")},
         [&](const RPCHelpMan &self, const Config &config,
             const JSONRPCRequest &request) -> UniValue {
             const BlockHash block_hash(
                 ParseHashV(request.params[0], "blockhash"));
             std::string filtertype_name = "basic";
             if (!request.params[1].isNull()) {
                 filtertype_name = request.params[1].get_str();
             }
 
             BlockFilterType filtertype;
             if (!BlockFilterTypeByName(filtertype_name, filtertype)) {
                 throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY,
                                    "Unknown filtertype");
             }
 
             BlockFilterIndex *index = GetBlockFilterIndex(filtertype);
             if (!index) {
                 throw JSONRPCError(RPC_MISC_ERROR,
                                    "Index is not enabled for filtertype " +
                                        filtertype_name);
             }
 
             const CBlockIndex *block_index;
             bool block_was_connected;
             {
                 LOCK(cs_main);
                 block_index = LookupBlockIndex(block_hash);
                 if (!block_index) {
                     throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY,
                                        "Block not found");
                 }
                 block_was_connected =
                     block_index->IsValid(BlockValidity::SCRIPTS);
             }
 
             bool index_ready = index->BlockUntilSyncedToCurrentChain();
 
             BlockFilter filter;
             uint256 filter_header;
             if (!index->LookupFilter(block_index, filter) ||
                 !index->LookupFilterHeader(block_index, filter_header)) {
                 int err_code;
                 std::string errmsg = "Filter not found.";
 
                 if (!block_was_connected) {
                     err_code = RPC_INVALID_ADDRESS_OR_KEY;
                     errmsg += " Block was not connected to active chain.";
                 } else if (!index_ready) {
                     err_code = RPC_MISC_ERROR;
                     errmsg += " Block filters are still in the process of "
                               "being indexed.";
                 } else {
                     err_code = RPC_INTERNAL_ERROR;
                     errmsg += " This error is unexpected and indicates index "
                               "corruption.";
                 }
 
                 throw JSONRPCError(err_code, errmsg);
             }
 
             UniValue ret(UniValue::VOBJ);
             ret.pushKV("filter", HexStr(filter.GetEncodedFilter()));
             ret.pushKV("header", filter_header.GetHex());
             return ret;
         },
     };
 }
 
 /**
  * Serialize the UTXO set to a file for loading elsewhere.
  *
  * @see SnapshotMetadata
  */
 static RPCHelpMan dumptxoutset() {
     return RPCHelpMan{
         "dumptxoutset",
         "Write the serialized UTXO set to disk.\n",
         {
             {"path", RPCArg::Type::STR, RPCArg::Optional::NO,
              "path to the output file. If relative, will be prefixed by "
              "datadir."},
         },
         RPCResult{RPCResult::Type::OBJ,
                   "",
                   "",
                   {
                       {RPCResult::Type::NUM, "coins_written",
                        "the number of coins written in the snapshot"},
                       {RPCResult::Type::STR_HEX, "base_hash",
                        "the hash of the base of the snapshot"},
                       {RPCResult::Type::NUM, "base_height",
                        "the height of the base of the snapshot"},
                       {RPCResult::Type::STR, "path",
                        "the absolute path that the snapshot was written to"},
                   }},
         RPCExamples{HelpExampleCli("dumptxoutset", "utxo.dat")},
         [&](const RPCHelpMan &self, const Config &config,
             const JSONRPCRequest &request) -> UniValue {
             fs::path path =
                 fs::absolute(request.params[0].get_str(), GetDataDir());
             // Write to a temporary path and then move into `path` on completion
             // to avoid confusion due to an interruption.
             fs::path temppath = fs::absolute(
                 request.params[0].get_str() + ".incomplete", GetDataDir());
 
             if (fs::exists(path)) {
                 throw JSONRPCError(RPC_INVALID_PARAMETER,
                                    path.string() +
                                        " already exists. If you are sure this "
                                        "is what you want, "
                                        "move it out of the way first");
             }
 
             FILE *file{fsbridge::fopen(temppath, "wb")};
             CAutoFile afile{file, SER_DISK, CLIENT_VERSION};
             std::unique_ptr<CCoinsViewCursor> pcursor;
             CCoinsStats stats;
             CBlockIndex *tip;
             NodeContext &node = EnsureNodeContext(request.context);
 
             {
                 // We need to lock cs_main to ensure that the coinsdb isn't
                 // written to between (i) flushing coins cache to disk
                 // (coinsdb), (ii) getting stats based upon the coinsdb, and
                 // (iii) constructing a cursor to the coinsdb for use below this
                 // block.
                 //
                 // Cursors returned by leveldb iterate over snapshots, so the
                 // contents of the pcursor will not be affected by simultaneous
                 // writes during use below this block.
                 //
                 // See discussion here:
                 //   https://github.com/bitcoin/bitcoin/pull/15606#discussion_r274479369
                 //
                 LOCK(::cs_main);
 
                 ::ChainstateActive().ForceFlushStateToDisk();
 
                 if (!GetUTXOStats(&::ChainstateActive().CoinsDB(), stats,
                                   CoinStatsHashType::NONE,
                                   node.rpc_interruption_point)) {
                     throw JSONRPCError(RPC_INTERNAL_ERROR,
                                        "Unable to read UTXO set");
                 }
 
                 pcursor = std::unique_ptr<CCoinsViewCursor>(
                     ::ChainstateActive().CoinsDB().Cursor());
                 tip = LookupBlockIndex(stats.hashBlock);
                 CHECK_NONFATAL(tip);
             }
 
             SnapshotMetadata metadata{tip->GetBlockHash(), stats.coins_count,
                                       uint64_t(tip->GetChainTxCount())};
 
             afile << metadata;
 
             COutPoint key;
             Coin coin;
             unsigned int iter{0};
 
             while (pcursor->Valid()) {
                 if (iter % 5000 == 0) {
                     node.rpc_interruption_point();
                 }
                 ++iter;
                 if (pcursor->GetKey(key) && pcursor->GetValue(coin)) {
                     afile << key;
                     afile << coin;
                 }
 
                 pcursor->Next();
             }
 
             afile.fclose();
             fs::rename(temppath, path);
 
             UniValue result(UniValue::VOBJ);
             result.pushKV("coins_written", stats.coins_count);
             result.pushKV("base_hash", tip->GetBlockHash().ToString());
             result.pushKV("base_height", tip->nHeight);
             result.pushKV("path", path.string());
             return result;
         },
     };
 }
 
 void RegisterBlockchainRPCCommands(CRPCTable &t) {
     // clang-format off
     static const CRPCCommand commands[] = {
         //  category            name                      actor (function)        argNames
         //  ------------------- ------------------------  ----------------------  ----------
         { "blockchain",         "getbestblockhash",       getbestblockhash,       {} },
         { "blockchain",         "getblock",               getblock,               {"blockhash","verbosity|verbose"} },
         { "blockchain",         "getblockchaininfo",      getblockchaininfo,      {} },
         { "blockchain",         "getblockcount",          getblockcount,          {} },
         { "blockchain",         "getblockhash",           getblockhash,           {"height"} },
         { "blockchain",         "getblockheader",         getblockheader,         {"blockhash","verbose"} },
         { "blockchain",         "getblockstats",          getblockstats,          {"hash_or_height","stats"} },
         { "blockchain",         "getchaintips",           getchaintips,           {} },
         { "blockchain",         "getchaintxstats",        getchaintxstats,        {"nblocks", "blockhash"} },
         { "blockchain",         "getdifficulty",            getdifficulty,            {} },
         { "blockchain",         "getmempoolancestors",    getmempoolancestors,    {"txid","verbose"} },
         { "blockchain",         "getmempooldescendants",  getmempooldescendants,  {"txid","verbose"} },
         { "blockchain",         "getmempoolentry",        getmempoolentry,        {"txid"} },
         { "blockchain",         "getmempoolinfo",         getmempoolinfo,         {} },
-        { "blockchain",         "getrawmempool",          getrawmempool,          {"verbose"} },
+        { "blockchain",         "getrawmempool",          getrawmempool,          {"verbose", "mempool_sequence"} },
         { "blockchain",         "gettxout",               gettxout,               {"txid","n","include_mempool"} },
         { "blockchain",         "gettxoutsetinfo",        gettxoutsetinfo,        {"hash_type"} },
         { "blockchain",         "pruneblockchain",        pruneblockchain,        {"height"} },
         { "blockchain",         "savemempool",            savemempool,            {} },
         { "blockchain",         "verifychain",            verifychain,            {"checklevel","nblocks"} },
         { "blockchain",         "preciousblock",          preciousblock,          {"blockhash"} },
         { "blockchain",         "scantxoutset",           scantxoutset,           {"action", "scanobjects"} },
         { "blockchain",         "getblockfilter",          getblockfilter,          {"blockhash", "filtertype"} },
 
         /* Not shown in help */
         { "hidden",             "getfinalizedblockhash",             getfinalizedblockhash,             {} },
         { "hidden",             "finalizeblock",                     finalizeblock,                     {"blockhash"} },
         { "hidden",             "invalidateblock",                  invalidateblock,                  {"blockhash"} },
         { "hidden",             "parkblock",                        parkblock,                        {"blockhash"} },
         { "hidden",             "reconsiderblock",                  reconsiderblock,                  {"blockhash"} },
         { "hidden",             "syncwithvalidationinterfacequeue", syncwithvalidationinterfacequeue, {} },
         { "hidden",             "dumptxoutset",                     dumptxoutset,                     {"path"} },
         { "hidden",             "unparkblock",                      unparkblock,                      {"blockhash"} },
         { "hidden",             "waitfornewblock",                  waitfornewblock,                  {"timeout"} },
         { "hidden",             "waitforblock",                     waitforblock,                     {"blockhash","timeout"} },
         { "hidden",             "waitforblockheight",               waitforblockheight,               {"height","timeout"} },
     };
     // clang-format on
     for (const auto &c : commands) {
         t.appendCommand(c.name, &c);
     }
 }
diff --git a/src/rpc/blockchain.h b/src/rpc/blockchain.h
index 6777702a6..87a6e57f6 100644
--- a/src/rpc/blockchain.h
+++ b/src/rpc/blockchain.h
@@ -1,57 +1,58 @@
 // Copyright (c) 2017-2019 The Bitcoin developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #ifndef BITCOIN_RPC_BLOCKCHAIN_H
 #define BITCOIN_RPC_BLOCKCHAIN_H
 
 #include <sync.h>
 
 #include <univalue.h>
 
 class CBlock;
 class CBlockIndex;
 class ChainstateManager;
 class CTxMemPool;
 class RPCHelpMan;
 struct NodeContext;
 namespace util {
 class Ref;
 } // namespace util
 
 extern RecursiveMutex cs_main;
 
 RPCHelpMan getblockchaininfo();
 
 /**
  * Get the required difficulty of the next block w/r/t the given block index.
  *
  * @return A floating point number that is a multiple of the main net minimum
  * difficulty (4295032833 hashes).
  */
 double GetDifficulty(const CBlockIndex *blockindex);
 
 /** Callback for when block tip changed. */
 void RPCNotifyBlockChange(const CBlockIndex *pindex);
 
 /** Block description to JSON */
 UniValue blockToJSON(const CBlock &block, const CBlockIndex *tip,
                      const CBlockIndex *blockindex, bool txDetails = false)
     LOCKS_EXCLUDED(cs_main);
 
 /** Mempool information to JSON */
 UniValue MempoolInfoToJSON(const CTxMemPool &pool);
 
 /** Mempool to JSON */
-UniValue MempoolToJSON(const CTxMemPool &pool, bool verbose = false);
+UniValue MempoolToJSON(const CTxMemPool &pool, bool verbose = false,
+                       bool include_mempool_sequence = false);
 
 /** Block header to JSON */
 UniValue blockheaderToJSON(const CBlockIndex *tip,
                            const CBlockIndex *blockindex)
     LOCKS_EXCLUDED(cs_main);
 
 NodeContext &EnsureNodeContext(const util::Ref &context);
 CTxMemPool &EnsureMemPool(const util::Ref &context);
 ChainstateManager &EnsureChainman(const util::Ref &context);
 
 #endif // BITCOIN_RPC_BLOCKCHAIN_H
diff --git a/src/rpc/client.cpp b/src/rpc/client.cpp
index 78c6f8c3d..1b14265f0 100644
--- a/src/rpc/client.cpp
+++ b/src/rpc/client.cpp
@@ -1,261 +1,262 @@
 // Copyright (c) 2010 Satoshi Nakamoto
 // Copyright (c) 2009-2016 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <rpc/client.h>
 #include <util/system.h>
 
 #include <cstdint>
 #include <set>
 
 class CRPCConvertParam {
 public:
     std::string methodName; //!< method whose params want conversion
     int paramIdx;           //!< 0-based idx of param to convert
     std::string paramName;  //!< parameter name
 };
 
 /**
  * Specify a (method, idx, name) here if the argument is a non-string RPC
  * argument and needs to be converted from JSON.
  *
  * @note Parameter indexes start from 0.
  */
 static const CRPCConvertParam vRPCConvertParams[] = {
     {"setmocktime", 0, "timestamp"},
     {"mockscheduler", 0, "delta_time"},
     {"utxoupdatepsbt", 1, "descriptors"},
     {"generatetoaddress", 0, "nblocks"},
     {"generatetoaddress", 2, "maxtries"},
     {"generatetodescriptor", 0, "num_blocks"},
     {"generatetodescriptor", 2, "maxtries"},
     {"generateblock", 1, "transactions"},
     {"getnetworkhashps", 0, "nblocks"},
     {"getnetworkhashps", 1, "height"},
     {"sendtoaddress", 1, "amount"},
     {"sendtoaddress", 4, "subtractfeefromamount"},
     {"sendtoaddress", 5, "avoid_reuse"},
     {"settxfee", 0, "amount"},
     {"sethdseed", 0, "newkeypool"},
     {"getreceivedbyaddress", 1, "minconf"},
     {"getreceivedbylabel", 1, "minconf"},
     {"listreceivedbyaddress", 0, "minconf"},
     {"listreceivedbyaddress", 1, "include_empty"},
     {"listreceivedbyaddress", 2, "include_watchonly"},
     {"listreceivedbylabel", 0, "minconf"},
     {"listreceivedbylabel", 1, "include_empty"},
     {"listreceivedbylabel", 2, "include_watchonly"},
     {"getbalance", 1, "minconf"},
     {"getbalance", 2, "include_watchonly"},
     {"getbalance", 3, "avoid_reuse"},
     {"getblockhash", 0, "height"},
     {"waitforblockheight", 0, "height"},
     {"waitforblockheight", 1, "timeout"},
     {"waitforblock", 1, "timeout"},
     {"waitfornewblock", 0, "timeout"},
     {"listtransactions", 1, "count"},
     {"listtransactions", 2, "skip"},
     {"listtransactions", 3, "include_watchonly"},
     {"walletpassphrase", 1, "timeout"},
     {"getblocktemplate", 0, "template_request"},
     {"listsinceblock", 1, "target_confirmations"},
     {"listsinceblock", 2, "include_watchonly"},
     {"listsinceblock", 3, "include_removed"},
     {"sendmany", 1, "amounts"},
     {"sendmany", 2, "minconf"},
     {"sendmany", 4, "subtractfeefrom"},
     {"deriveaddresses", 1, "range"},
     {"scantxoutset", 1, "scanobjects"},
     {"addmultisigaddress", 0, "nrequired"},
     {"addmultisigaddress", 1, "keys"},
     {"createmultisig", 0, "nrequired"},
     {"createmultisig", 1, "keys"},
     {"listunspent", 0, "minconf"},
     {"listunspent", 1, "maxconf"},
     {"listunspent", 2, "addresses"},
     {"listunspent", 3, "include_unsafe"},
     {"listunspent", 4, "query_options"},
     {"getblock", 1, "verbosity"},
     {"getblock", 1, "verbose"},
     {"getblockheader", 1, "verbose"},
     {"getchaintxstats", 0, "nblocks"},
     {"gettransaction", 1, "include_watchonly"},
     {"gettransaction", 2, "verbose"},
     {"getrawtransaction", 1, "verbose"},
     {"createrawtransaction", 0, "inputs"},
     {"createrawtransaction", 1, "outputs"},
     {"createrawtransaction", 2, "locktime"},
     {"signrawtransactionwithkey", 1, "privkeys"},
     {"signrawtransactionwithkey", 2, "prevtxs"},
     {"signrawtransactionwithwallet", 1, "prevtxs"},
     {"sendrawtransaction", 1, "maxfeerate"},
     {"testmempoolaccept", 0, "rawtxs"},
     {"testmempoolaccept", 1, "maxfeerate"},
     {"combinerawtransaction", 0, "txs"},
     {"fundrawtransaction", 1, "options"},
     {"walletcreatefundedpsbt", 0, "inputs"},
     {"walletcreatefundedpsbt", 1, "outputs"},
     {"walletcreatefundedpsbt", 2, "locktime"},
     {"walletcreatefundedpsbt", 3, "options"},
     {"walletcreatefundedpsbt", 4, "bip32derivs"},
     {"walletprocesspsbt", 1, "sign"},
     {"walletprocesspsbt", 3, "bip32derivs"},
     {"createpsbt", 0, "inputs"},
     {"createpsbt", 1, "outputs"},
     {"createpsbt", 2, "locktime"},
     {"combinepsbt", 0, "txs"},
     {"joinpsbts", 0, "txs"},
     {"finalizepsbt", 1, "extract"},
     {"converttopsbt", 1, "permitsigdata"},
     {"gettxout", 1, "n"},
     {"gettxout", 2, "include_mempool"},
     {"gettxoutproof", 0, "txids"},
     {"lockunspent", 0, "unlock"},
     {"lockunspent", 1, "transactions"},
     {"send", 0, "outputs"},
     {"send", 1, "options"},
     {"importprivkey", 2, "rescan"},
     {"importaddress", 2, "rescan"},
     {"importaddress", 3, "p2sh"},
     {"importpubkey", 2, "rescan"},
     {"importmulti", 0, "requests"},
     {"importmulti", 1, "options"},
     {"importdescriptors", 0, "requests"},
     {"verifychain", 0, "checklevel"},
     {"verifychain", 1, "nblocks"},
     {"getblockstats", 0, "hash_or_height"},
     {"getblockstats", 1, "stats"},
     {"pruneblockchain", 0, "height"},
     {"keypoolrefill", 0, "newsize"},
     {"getrawmempool", 0, "verbose"},
+    {"getrawmempool", 1, "mempool_sequence"},
     {"prioritisetransaction", 1, "dummy"},
     {"prioritisetransaction", 2, "fee_delta"},
     {"setban", 2, "bantime"},
     {"setban", 3, "absolute"},
     {"setnetworkactive", 0, "state"},
     {"setwalletflag", 1, "value"},
     {"getmempoolancestors", 1, "verbose"},
     {"getmempooldescendants", 1, "verbose"},
     {"disconnectnode", 1, "nodeid"},
     {"logging", 0, "include"},
     {"logging", 1, "exclude"},
     {"upgradewallet", 0, "version"},
     // Echo with conversion (For testing only)
     {"echojson", 0, "arg0"},
     {"echojson", 1, "arg1"},
     {"echojson", 2, "arg2"},
     {"echojson", 3, "arg3"},
     {"echojson", 4, "arg4"},
     {"echojson", 5, "arg5"},
     {"echojson", 6, "arg6"},
     {"echojson", 7, "arg7"},
     {"echojson", 8, "arg8"},
     {"echojson", 9, "arg9"},
     {"rescanblockchain", 0, "start_height"},
     {"rescanblockchain", 1, "stop_height"},
     {"createwallet", 1, "disable_private_keys"},
     {"createwallet", 2, "blank"},
     {"createwallet", 4, "avoid_reuse"},
     {"createwallet", 5, "descriptors"},
     {"createwallet", 6, "load_on_startup"},
     {"loadwallet", 1, "load_on_startup"},
     {"unloadwallet", 1, "load_on_startup"},
     {"getnodeaddresses", 0, "count"},
     {"addpeeraddress", 1, "port"},
     {"stop", 0, "wait"},
     // Avalanche
     {"addavalanchenode", 0, "nodeid"},
     {"buildavalancheproof", 0, "sequence"},
     {"buildavalancheproof", 1, "expiration"},
     {"buildavalancheproof", 3, "stakes"},
 };
 
 class CRPCConvertTable {
 private:
     std::set<std::pair<std::string, int>> members;
     std::set<std::pair<std::string, std::string>> membersByName;
 
 public:
     CRPCConvertTable();
 
     bool convert(const std::string &method, int idx) {
         return (members.count(std::make_pair(method, idx)) > 0);
     }
     bool convert(const std::string &method, const std::string &name) {
         return (membersByName.count(std::make_pair(method, name)) > 0);
     }
 };
 
 CRPCConvertTable::CRPCConvertTable() {
     const unsigned int n_elem =
         (sizeof(vRPCConvertParams) / sizeof(vRPCConvertParams[0]));
 
     for (unsigned int i = 0; i < n_elem; i++) {
         members.insert(std::make_pair(vRPCConvertParams[i].methodName,
                                       vRPCConvertParams[i].paramIdx));
         membersByName.insert(std::make_pair(vRPCConvertParams[i].methodName,
                                             vRPCConvertParams[i].paramName));
     }
 }
 
 static CRPCConvertTable rpcCvtTable;
 
 /**
  * Non-RFC4627 JSON parser, accepts internal values (such as numbers, true,
  * false, null) as well as objects and arrays.
  */
 UniValue ParseNonRFCJSONValue(const std::string &strVal) {
     UniValue jVal;
     if (!jVal.read(std::string("[") + strVal + std::string("]")) ||
         !jVal.isArray() || jVal.size() != 1) {
         throw std::runtime_error(std::string("Error parsing JSON: ") + strVal);
     }
     return jVal[0];
 }
 
 UniValue RPCConvertValues(const std::string &strMethod,
                           const std::vector<std::string> &strParams) {
     UniValue params(UniValue::VARR);
 
     for (unsigned int idx = 0; idx < strParams.size(); idx++) {
         const std::string &strVal = strParams[idx];
 
         if (!rpcCvtTable.convert(strMethod, idx)) {
             // insert string value directly
             params.push_back(strVal);
         } else {
             // parse string as JSON, insert bool/number/object/etc. value
             params.push_back(ParseNonRFCJSONValue(strVal));
         }
     }
 
     return params;
 }
 
 UniValue RPCConvertNamedValues(const std::string &strMethod,
                                const std::vector<std::string> &strParams) {
     UniValue params(UniValue::VOBJ);
 
     for (const std::string &s : strParams) {
         size_t pos = s.find('=');
         if (pos == std::string::npos) {
             throw(std::runtime_error("No '=' in named argument '" + s +
                                      "', this needs to be present for every "
                                      "argument (even if it is empty)"));
         }
 
         std::string name = s.substr(0, pos);
         std::string value = s.substr(pos + 1);
 
         if (!rpcCvtTable.convert(strMethod, name)) {
             // insert string value directly
             params.pushKV(name, value);
         } else {
             // parse string as JSON, insert bool/number/object/etc. value
             params.pushKV(name, ParseNonRFCJSONValue(value));
         }
     }
 
     return params;
 }
diff --git a/src/txmempool.cpp b/src/txmempool.cpp
index a1848667e..a438a536f 100644
--- a/src/txmempool.cpp
+++ b/src/txmempool.cpp
@@ -1,1459 +1,1463 @@
 // Copyright (c) 2009-2010 Satoshi Nakamoto
 // Copyright (c) 2009-2016 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <txmempool.h>
 
 #include <chain.h>
 #include <chainparams.h> // for GetConsensus.
 #include <clientversion.h>
 #include <config.h>
 #include <consensus/consensus.h>
 #include <consensus/tx_verify.h>
 #include <consensus/validation.h>
 #include <policy/fees.h>
 #include <policy/policy.h>
 #include <policy/settings.h>
 #include <reverse_iterator.h>
 #include <util/moneystr.h>
 #include <util/system.h>
 #include <util/time.h>
 #include <validation.h>
 #include <validationinterface.h>
 #include <version.h>
 
 #include <algorithm>
 
 CTxMemPoolEntry::CTxMemPoolEntry(const CTransactionRef &_tx, const Amount _nFee,
                                  int64_t _nTime, unsigned int _entryHeight,
                                  bool _spendsCoinbase, int64_t _sigOpsCount,
                                  LockPoints lp)
     : tx(_tx), nFee(_nFee), nTxSize(tx->GetTotalSize()),
       nUsageSize(RecursiveDynamicUsage(tx)), nTime(_nTime),
       entryHeight(_entryHeight), spendsCoinbase(_spendsCoinbase),
       sigOpCount(_sigOpsCount), lockPoints(lp), m_epoch(0) {
     nCountWithDescendants = 1;
     nSizeWithDescendants = GetTxSize();
     nSigOpCountWithDescendants = sigOpCount;
     nModFeesWithDescendants = nFee;
 
     feeDelta = Amount::zero();
 
     nCountWithAncestors = 1;
     nSizeWithAncestors = GetTxSize();
     nModFeesWithAncestors = nFee;
     nSigOpCountWithAncestors = sigOpCount;
 }
 
 size_t CTxMemPoolEntry::GetTxVirtualSize() const {
     return GetVirtualTransactionSize(nTxSize, sigOpCount);
 }
 
 uint64_t CTxMemPoolEntry::GetVirtualSizeWithDescendants() const {
     // note this is distinct from the sum of descendants' individual virtual
     // sizes, and may be smaller.
     return GetVirtualTransactionSize(nSizeWithDescendants,
                                      nSigOpCountWithDescendants);
 }
 
 uint64_t CTxMemPoolEntry::GetVirtualSizeWithAncestors() const {
     // note this is distinct from the sum of ancestors' individual virtual
     // sizes, and may be smaller.
     return GetVirtualTransactionSize(nSizeWithAncestors,
                                      nSigOpCountWithAncestors);
 }
 
 void CTxMemPoolEntry::UpdateFeeDelta(Amount newFeeDelta) {
     nModFeesWithDescendants += newFeeDelta - feeDelta;
     nModFeesWithAncestors += newFeeDelta - feeDelta;
     feeDelta = newFeeDelta;
 }
 
 void CTxMemPoolEntry::UpdateLockPoints(const LockPoints &lp) {
     lockPoints = lp;
 }
 
 // Update the given tx for any in-mempool descendants.
 // Assumes that CTxMemPool::m_children is correct for the given tx and all
 // descendants.
 void CTxMemPool::UpdateForDescendants(txiter updateIt,
                                       cacheMap &cachedDescendants,
                                       const std::set<TxId> &setExclude) {
     CTxMemPoolEntry::Children stageEntries, descendants;
     stageEntries = updateIt->GetMemPoolChildrenConst();
 
     while (!stageEntries.empty()) {
         const CTxMemPoolEntry &descendant = *stageEntries.begin();
         descendants.insert(descendant);
         stageEntries.erase(descendant);
         const CTxMemPoolEntry::Children &children =
             descendant.GetMemPoolChildrenConst();
         for (const CTxMemPoolEntry &childEntry : children) {
             cacheMap::iterator cacheIt =
                 cachedDescendants.find(mapTx.iterator_to(childEntry));
             if (cacheIt != cachedDescendants.end()) {
                 // We've already calculated this one, just add the entries for
                 // this set but don't traverse again.
                 for (txiter cacheEntry : cacheIt->second) {
                     descendants.insert(*cacheEntry);
                 }
             } else if (!descendants.count(childEntry)) {
                 // Schedule for later processing
                 stageEntries.insert(childEntry);
             }
         }
     }
     // descendants now contains all in-mempool descendants of updateIt.
     // Update and add to cached descendant map
     int64_t modifySize = 0;
     int64_t modifyCount = 0;
     Amount modifyFee = Amount::zero();
     int64_t modifySigOpCount = 0;
     for (const CTxMemPoolEntry &descendant : descendants) {
         if (!setExclude.count(descendant.GetTx().GetId())) {
             modifySize += descendant.GetTxSize();
             modifyFee += descendant.GetModifiedFee();
             modifyCount++;
             modifySigOpCount += descendant.GetSigOpCount();
             cachedDescendants[updateIt].insert(mapTx.iterator_to(descendant));
             // Update ancestor state for each descendant
             mapTx.modify(mapTx.iterator_to(descendant),
                          update_ancestor_state(updateIt->GetTxSize(),
                                                updateIt->GetModifiedFee(), 1,
                                                updateIt->GetSigOpCount()));
         }
     }
     mapTx.modify(updateIt,
                  update_descendant_state(modifySize, modifyFee, modifyCount,
                                          modifySigOpCount));
 }
 
 // txidsToUpdate is the set of transaction hashes from a disconnected block
 // which has been re-added to the mempool. For each entry, look for descendants
 // that are outside txidsToUpdate, and add fee/size information for such
 // descendants to the parent. For each such descendant, also update the ancestor
 // state to include the parent.
 void CTxMemPool::UpdateTransactionsFromBlock(
     const std::vector<TxId> &txidsToUpdate) {
     AssertLockHeld(cs);
     // For each entry in txidsToUpdate, store the set of in-mempool, but not
     // in-txidsToUpdate transactions, so that we don't have to recalculate
     // descendants when we come across a previously seen entry.
     cacheMap mapMemPoolDescendantsToUpdate;
 
     // Use a set for lookups into txidsToUpdate (these entries are already
     // accounted for in the state of their ancestors)
     std::set<TxId> setAlreadyIncluded(txidsToUpdate.begin(),
                                       txidsToUpdate.end());
 
     // Iterate in reverse, so that whenever we are looking at a transaction
     // we are sure that all in-mempool descendants have already been processed.
     // This maximizes the benefit of the descendant cache and guarantees that
     // CTxMemPool::m_children will be updated, an assumption made in
     // UpdateForDescendants.
     for (const TxId &txid : reverse_iterate(txidsToUpdate)) {
         // calculate children from mapNextTx
         txiter it = mapTx.find(txid);
         if (it == mapTx.end()) {
             continue;
         }
 
         auto iter = mapNextTx.lower_bound(COutPoint(txid, 0));
         // First calculate the children, and update CTxMemPool::m_children to
         // include them, and update their CTxMemPoolEntry::m_parents to include
         // this tx. we cache the in-mempool children to avoid duplicate updates
         {
             const auto epoch = GetFreshEpoch();
             for (; iter != mapNextTx.end() && iter->first->GetTxId() == txid;
                  ++iter) {
                 const TxId &childTxId = iter->second->GetId();
                 txiter childIter = mapTx.find(childTxId);
                 assert(childIter != mapTx.end());
                 // We can skip updating entries we've encountered before or that
                 // are in the block (which are already accounted for).
                 if (!visited(childIter) &&
                     !setAlreadyIncluded.count(childTxId)) {
                     UpdateChild(it, childIter, true);
                     UpdateParent(childIter, it, true);
                 }
             }
         } // release epoch guard for UpdateForDescendants
         UpdateForDescendants(it, mapMemPoolDescendantsToUpdate,
                              setAlreadyIncluded);
     }
 }
 
 bool CTxMemPool::CalculateMemPoolAncestors(
     const CTxMemPoolEntry &entry, setEntries &setAncestors,
     uint64_t limitAncestorCount, uint64_t limitAncestorSize,
     uint64_t limitDescendantCount, uint64_t limitDescendantSize,
     std::string &errString, bool fSearchForParents /* = true */) const {
     CTxMemPoolEntry::Parents staged_ancestors;
     const CTransaction &tx = entry.GetTx();
 
     if (fSearchForParents) {
         // Get parents of this transaction that are in the mempool
         // GetMemPoolParents() is only valid for entries in the mempool, so we
         // iterate mapTx to find parents.
         for (const CTxIn &in : tx.vin) {
             std::optional<txiter> piter = GetIter(in.prevout.GetTxId());
             if (!piter) {
                 continue;
             }
             staged_ancestors.insert(**piter);
             if (staged_ancestors.size() + 1 > limitAncestorCount) {
                 errString =
                     strprintf("too many unconfirmed parents [limit: %u]",
                               limitAncestorCount);
                 return false;
             }
         }
     } else {
         // If we're not searching for parents, we require this to be an entry in
         // the mempool already.
         txiter it = mapTx.iterator_to(entry);
         staged_ancestors = it->GetMemPoolParentsConst();
     }
 
     size_t totalSizeWithAncestors = entry.GetTxSize();
 
     while (!staged_ancestors.empty()) {
         const CTxMemPoolEntry &stage = staged_ancestors.begin()->get();
         txiter stageit = mapTx.iterator_to(stage);
 
         setAncestors.insert(stageit);
         staged_ancestors.erase(stage);
         totalSizeWithAncestors += stageit->GetTxSize();
 
         if (stageit->GetSizeWithDescendants() + entry.GetTxSize() >
             limitDescendantSize) {
             errString = strprintf(
                 "exceeds descendant size limit for tx %s [limit: %u]",
                 stageit->GetTx().GetId().ToString(), limitDescendantSize);
             return false;
         }
 
         if (stageit->GetCountWithDescendants() + 1 > limitDescendantCount) {
             errString = strprintf("too many descendants for tx %s [limit: %u]",
                                   stageit->GetTx().GetId().ToString(),
                                   limitDescendantCount);
             return false;
         }
 
         if (totalSizeWithAncestors > limitAncestorSize) {
             errString = strprintf("exceeds ancestor size limit [limit: %u]",
                                   limitAncestorSize);
             return false;
         }
 
         const CTxMemPoolEntry::Parents &parents =
             stageit->GetMemPoolParentsConst();
         for (const CTxMemPoolEntry &parent : parents) {
             txiter parent_it = mapTx.iterator_to(parent);
 
             // If this is a new ancestor, add it.
             if (setAncestors.count(parent_it) == 0) {
                 staged_ancestors.insert(parent);
             }
             if (staged_ancestors.size() + setAncestors.size() + 1 >
                 limitAncestorCount) {
                 errString =
                     strprintf("too many unconfirmed ancestors [limit: %u]",
                               limitAncestorCount);
                 return false;
             }
         }
     }
 
     return true;
 }
 
 void CTxMemPool::UpdateAncestorsOf(bool add, txiter it,
                                    setEntries &setAncestors) {
     CTxMemPoolEntry::Parents parents = it->GetMemPoolParents();
     // add or remove this tx as a child of each parent
     for (const CTxMemPoolEntry &parent : parents) {
         UpdateChild(mapTx.iterator_to(parent), it, add);
     }
     const int64_t updateCount = (add ? 1 : -1);
     const int64_t updateSize = updateCount * it->GetTxSize();
     const int64_t updateSigOpCount = updateCount * it->GetSigOpCount();
     const Amount updateFee = updateCount * it->GetModifiedFee();
     for (txiter ancestorIt : setAncestors) {
         mapTx.modify(ancestorIt,
                      update_descendant_state(updateSize, updateFee, updateCount,
                                              updateSigOpCount));
     }
 }
 
 void CTxMemPool::UpdateEntryForAncestors(txiter it,
                                          const setEntries &setAncestors) {
     int64_t updateCount = setAncestors.size();
     int64_t updateSize = 0;
     int64_t updateSigOpsCount = 0;
     Amount updateFee = Amount::zero();
 
     for (txiter ancestorIt : setAncestors) {
         updateSize += ancestorIt->GetTxSize();
         updateFee += ancestorIt->GetModifiedFee();
         updateSigOpsCount += ancestorIt->GetSigOpCount();
     }
     mapTx.modify(it, update_ancestor_state(updateSize, updateFee, updateCount,
                                            updateSigOpsCount));
 }
 
 void CTxMemPool::UpdateChildrenForRemoval(txiter it) {
     const CTxMemPoolEntry::Children &children = it->GetMemPoolChildrenConst();
     for (const CTxMemPoolEntry &updateIt : children) {
         UpdateParent(mapTx.iterator_to(updateIt), it, false);
     }
 }
 
 void CTxMemPool::UpdateForRemoveFromMempool(const setEntries &entriesToRemove,
                                             bool updateDescendants) {
     // For each entry, walk back all ancestors and decrement size associated
     // with this transaction.
     const uint64_t nNoLimit = std::numeric_limits<uint64_t>::max();
     if (updateDescendants) {
         // updateDescendants should be true whenever we're not recursively
         // removing a tx and all its descendants, eg when a transaction is
         // confirmed in a block.
         // Here we only update statistics and not data in CTxMemPool::Parents
         // and CTxMemPoolEntry::Children (which we need to preserve until we're
         // finished with all operations that need to traverse the mempool).
         for (txiter removeIt : entriesToRemove) {
             setEntries setDescendants;
             CalculateDescendants(removeIt, setDescendants);
             setDescendants.erase(removeIt); // don't update state for self
             int64_t modifySize = -int64_t(removeIt->GetTxSize());
             Amount modifyFee = -1 * removeIt->GetModifiedFee();
             int modifySigOps = -removeIt->GetSigOpCount();
             for (txiter dit : setDescendants) {
                 mapTx.modify(dit, update_ancestor_state(modifySize, modifyFee,
                                                         -1, modifySigOps));
             }
         }
     }
 
     for (txiter removeIt : entriesToRemove) {
         setEntries setAncestors;
         const CTxMemPoolEntry &entry = *removeIt;
         std::string dummy;
         // Since this is a tx that is already in the mempool, we can call CMPA
         // with fSearchForParents = false.  If the mempool is in a consistent
         // state, then using true or false should both be correct, though false
         // should be a bit faster.
         // However, if we happen to be in the middle of processing a reorg, then
         // the mempool can be in an inconsistent state.  In this case, the set
         // of ancestors reachable via GetMemPoolParents()/GetMemPoolChildren()
         // will be the same as the set of ancestors whose packages include this
         // transaction, because when we add a new transaction to the mempool in
         // addUnchecked(), we assume it has no children, and in the case of a
         // reorg where that assumption is false, the in-mempool children aren't
         // linked to the in-block tx's until UpdateTransactionsFromBlock() is
         // called.
         // So if we're being called during a reorg, ie before
         // UpdateTransactionsFromBlock() has been called, then
         // GetMemPoolParents()/GetMemPoolChildren() will differ from the set of
         // mempool parents we'd calculate by searching, and it's important that
         // we use the cached notion of ancestor transactions as the set of
         // things to update for removal.
         CalculateMemPoolAncestors(entry, setAncestors, nNoLimit, nNoLimit,
                                   nNoLimit, nNoLimit, dummy, false);
         // Note that UpdateAncestorsOf severs the child links that point to
         // removeIt in the entries for the parents of removeIt.
         UpdateAncestorsOf(false, removeIt, setAncestors);
     }
     // After updating all the ancestor sizes, we can now sever the link between
     // each transaction being removed and any mempool children (ie, update
     // CTxMemPoolEntry::m_parents for each direct child of a transaction being
     // removed).
     for (txiter removeIt : entriesToRemove) {
         UpdateChildrenForRemoval(removeIt);
     }
 }
 
 void CTxMemPoolEntry::UpdateDescendantState(int64_t modifySize,
                                             Amount modifyFee,
                                             int64_t modifyCount,
                                             int64_t modifySigOpCount) {
     nSizeWithDescendants += modifySize;
     assert(int64_t(nSizeWithDescendants) > 0);
     nModFeesWithDescendants += modifyFee;
     nCountWithDescendants += modifyCount;
     assert(int64_t(nCountWithDescendants) > 0);
     nSigOpCountWithDescendants += modifySigOpCount;
     assert(int64_t(nSigOpCountWithDescendants) >= 0);
 }
 
 void CTxMemPoolEntry::UpdateAncestorState(int64_t modifySize, Amount modifyFee,
                                           int64_t modifyCount,
                                           int64_t modifySigOps) {
     nSizeWithAncestors += modifySize;
     assert(int64_t(nSizeWithAncestors) > 0);
     nModFeesWithAncestors += modifyFee;
     nCountWithAncestors += modifyCount;
     assert(int64_t(nCountWithAncestors) > 0);
     nSigOpCountWithAncestors += modifySigOps;
     assert(int(nSigOpCountWithAncestors) >= 0);
 }
 
 CTxMemPool::CTxMemPool()
     : nTransactionsUpdated(0), m_epoch(0), m_has_epoch_guard(false) {
     // lock free clear
     _clear();
 
     // Sanity checks off by default for performance, because otherwise accepting
     // transactions becomes O(N^2) where N is the number of transactions in the
     // pool
     nCheckFrequency = 0;
 }
 
 CTxMemPool::~CTxMemPool() {}
 
 bool CTxMemPool::isSpent(const COutPoint &outpoint) const {
     LOCK(cs);
     return mapNextTx.count(outpoint);
 }
 
 unsigned int CTxMemPool::GetTransactionsUpdated() const {
     return nTransactionsUpdated;
 }
 
 void CTxMemPool::AddTransactionsUpdated(unsigned int n) {
     nTransactionsUpdated += n;
 }
 
 void CTxMemPool::addUnchecked(const CTxMemPoolEntry &entry,
                               setEntries &setAncestors) {
     // Add to memory pool without checking anything.
     // Used by AcceptToMemoryPool(), which DOES do all the appropriate checks.
     indexed_transaction_set::iterator newit = mapTx.insert(entry).first;
 
     // Update transaction for any feeDelta created by PrioritiseTransaction
     // TODO: refactor so that the fee delta is calculated before inserting into
     // mapTx.
     Amount feeDelta = Amount::zero();
     ApplyDelta(entry.GetTx().GetId(), feeDelta);
     if (feeDelta != Amount::zero()) {
         mapTx.modify(newit, update_fee_delta(feeDelta));
     }
 
     // Update cachedInnerUsage to include contained transaction's usage.
     // (When we update the entry for in-mempool parents, memory usage will be
     // further updated.)
     cachedInnerUsage += entry.DynamicMemoryUsage();
 
     const CTransaction &tx = newit->GetTx();
     std::set<TxId> setParentTransactions;
     for (const CTxIn &in : tx.vin) {
         mapNextTx.insert(std::make_pair(&in.prevout, &tx));
         setParentTransactions.insert(in.prevout.GetTxId());
     }
     // Don't bother worrying about child transactions of this one. Normal case
     // of a new transaction arriving is that there can't be any children,
     // because such children would be orphans. An exception to that is if a
     // transaction enters that used to be in a block. In that case, our
     // disconnect block logic will call UpdateTransactionsFromBlock to clean up
     // the mess we're leaving here.
 
     // Update ancestors with information about this tx
     for (const auto &pit : GetIterSet(setParentTransactions)) {
         UpdateParent(newit, pit, true);
     }
     UpdateAncestorsOf(true, newit, setAncestors);
     UpdateEntryForAncestors(newit, setAncestors);
 
     nTransactionsUpdated++;
     totalTxSize += entry.GetTxSize();
 
     vTxHashes.emplace_back(tx.GetHash(), newit);
     newit->vTxHashesIdx = vTxHashes.size() - 1;
 }
 
 void CTxMemPool::removeUnchecked(txiter it, MemPoolRemovalReason reason) {
+    // We increment mempool sequence value no matter removal reason
+    // even if not directly reported below.
+    uint64_t mempool_sequence = GetAndIncrementSequence();
+
     if (reason != MemPoolRemovalReason::BLOCK) {
         // Notify clients that a transaction has been removed from the mempool
         // for any reason except being included in a block. Clients interested
         // in transactions included in blocks can subscribe to the
         // BlockConnected notification.
-        GetMainSignals().TransactionRemovedFromMempool(it->GetSharedTx(),
-                                                       reason);
+        GetMainSignals().TransactionRemovedFromMempool(
+            it->GetSharedTx(), reason, mempool_sequence);
     }
 
     for (const CTxIn &txin : it->GetTx().vin) {
         mapNextTx.erase(txin.prevout);
     }
 
     /* add logging because unchecked */
     RemoveUnbroadcastTx(it->GetTx().GetId(), true);
 
     if (vTxHashes.size() > 1) {
         vTxHashes[it->vTxHashesIdx] = std::move(vTxHashes.back());
         vTxHashes[it->vTxHashesIdx].second->vTxHashesIdx = it->vTxHashesIdx;
         vTxHashes.pop_back();
         if (vTxHashes.size() * 2 < vTxHashes.capacity()) {
             vTxHashes.shrink_to_fit();
         }
     } else {
         vTxHashes.clear();
     }
 
     totalTxSize -= it->GetTxSize();
     cachedInnerUsage -= it->DynamicMemoryUsage();
     cachedInnerUsage -= memusage::DynamicUsage(it->GetMemPoolParentsConst()) +
                         memusage::DynamicUsage(it->GetMemPoolChildrenConst());
     mapTx.erase(it);
     nTransactionsUpdated++;
 }
 
 // Calculates descendants of entry that are not already in setDescendants, and
 // adds to setDescendants. Assumes entryit is already a tx in the mempool and
 // CTxMemPoolEntry::m_children is correct for tx and all descendants. Also
 // assumes that if an entry is in setDescendants already, then all in-mempool
 // descendants of it are already in setDescendants as well, so that we can save
 // time by not iterating over those entries.
 void CTxMemPool::CalculateDescendants(txiter entryit,
                                       setEntries &setDescendants) const {
     setEntries stage;
     if (setDescendants.count(entryit) == 0) {
         stage.insert(entryit);
     }
     // Traverse down the children of entry, only adding children that are not
     // accounted for in setDescendants already (because those children have
     // either already been walked, or will be walked in this iteration).
     while (!stage.empty()) {
         txiter it = *stage.begin();
         setDescendants.insert(it);
         stage.erase(it);
 
         const CTxMemPoolEntry::Children &children =
             it->GetMemPoolChildrenConst();
         for (const CTxMemPoolEntry &child : children) {
             txiter childiter = mapTx.iterator_to(child);
             if (!setDescendants.count(childiter)) {
                 stage.insert(childiter);
             }
         }
     }
 }
 
 void CTxMemPool::removeRecursive(const CTransaction &origTx,
                                  MemPoolRemovalReason reason) {
     // Remove transaction from memory pool.
     AssertLockHeld(cs);
     setEntries txToRemove;
     txiter origit = mapTx.find(origTx.GetId());
     if (origit != mapTx.end()) {
         txToRemove.insert(origit);
     } else {
         // When recursively removing but origTx isn't in the mempool be sure to
         // remove any children that are in the pool. This can happen during
         // chain re-orgs if origTx isn't re-accepted into the mempool for any
         // reason.
         for (size_t i = 0; i < origTx.vout.size(); i++) {
             auto it = mapNextTx.find(COutPoint(origTx.GetId(), i));
             if (it == mapNextTx.end()) {
                 continue;
             }
 
             txiter nextit = mapTx.find(it->second->GetId());
             assert(nextit != mapTx.end());
             txToRemove.insert(nextit);
         }
     }
 
     setEntries setAllRemoves;
     for (txiter it : txToRemove) {
         CalculateDescendants(it, setAllRemoves);
     }
 
     RemoveStaged(setAllRemoves, false, reason);
 }
 
 void CTxMemPool::removeForReorg(const Config &config,
                                 const CCoinsViewCache *pcoins,
                                 unsigned int nMemPoolHeight, int flags) {
     // Remove transactions spending a coinbase which are now immature and
     // no-longer-final transactions.
     AssertLockHeld(cs);
     setEntries txToRemove;
     for (indexed_transaction_set::const_iterator it = mapTx.begin();
          it != mapTx.end(); it++) {
         const CTransaction &tx = it->GetTx();
         LockPoints lp = it->GetLockPoints();
         bool validLP = TestLockPointValidity(&lp);
 
         TxValidationState state;
         if (!ContextualCheckTransactionForCurrentBlock(
                 config.GetChainParams().GetConsensus(), tx, state, flags) ||
             !CheckSequenceLocks(*this, tx, flags, &lp, validLP)) {
             // Note if CheckSequenceLocks fails the LockPoints may still be
             // invalid. So it's critical that we remove the tx and not depend on
             // the LockPoints.
             txToRemove.insert(it);
         } else if (it->GetSpendsCoinbase()) {
             for (const CTxIn &txin : tx.vin) {
                 indexed_transaction_set::const_iterator it2 =
                     mapTx.find(txin.prevout.GetTxId());
                 if (it2 != mapTx.end()) {
                     continue;
                 }
 
                 const Coin &coin = pcoins->AccessCoin(txin.prevout);
                 if (nCheckFrequency != 0) {
                     assert(!coin.IsSpent());
                 }
 
                 if (coin.IsSpent() ||
                     (coin.IsCoinBase() &&
                      int64_t(nMemPoolHeight) - coin.GetHeight() <
                          COINBASE_MATURITY)) {
                     txToRemove.insert(it);
                     break;
                 }
             }
         }
         if (!validLP) {
             mapTx.modify(it, update_lock_points(lp));
         }
     }
     setEntries setAllRemoves;
     for (txiter it : txToRemove) {
         CalculateDescendants(it, setAllRemoves);
     }
     RemoveStaged(setAllRemoves, false, MemPoolRemovalReason::REORG);
 }
 
 void CTxMemPool::removeConflicts(const CTransaction &tx) {
     // Remove transactions which depend on inputs of tx, recursively
     AssertLockHeld(cs);
     for (const CTxIn &txin : tx.vin) {
         auto it = mapNextTx.find(txin.prevout);
         if (it != mapNextTx.end()) {
             const CTransaction &txConflict = *it->second;
             if (txConflict != tx) {
                 ClearPrioritisation(txConflict.GetId());
                 removeRecursive(txConflict, MemPoolRemovalReason::CONFLICT);
             }
         }
     }
 }
 
 /**
  * Called when a block is connected. Removes from mempool and updates the miner
  * fee estimator.
  */
 void CTxMemPool::removeForBlock(const std::vector<CTransactionRef> &vtx,
                                 unsigned int nBlockHeight) {
     AssertLockHeld(cs);
 
     DisconnectedBlockTransactions disconnectpool;
     disconnectpool.addForBlock(vtx, *this);
 
     std::vector<const CTxMemPoolEntry *> entries;
     for (const CTransactionRef &tx :
          reverse_iterate(disconnectpool.GetQueuedTx().get<insertion_order>())) {
         const TxId &txid = tx->GetId();
 
         indexed_transaction_set::iterator i = mapTx.find(txid);
         if (i != mapTx.end()) {
             entries.push_back(&*i);
         }
     }
 
     for (const CTransactionRef &tx :
          reverse_iterate(disconnectpool.GetQueuedTx().get<insertion_order>())) {
         txiter it = mapTx.find(tx->GetId());
         if (it != mapTx.end()) {
             setEntries stage;
             stage.insert(it);
             RemoveStaged(stage, true, MemPoolRemovalReason::BLOCK);
         }
         removeConflicts(*tx);
         ClearPrioritisation(tx->GetId());
     }
 
     disconnectpool.clear();
 
     lastRollingFeeUpdate = GetTime();
     blockSinceLastRollingFeeBump = true;
 }
 
 void CTxMemPool::_clear() {
     mapTx.clear();
     mapNextTx.clear();
     vTxHashes.clear();
     totalTxSize = 0;
     cachedInnerUsage = 0;
     lastRollingFeeUpdate = GetTime();
     blockSinceLastRollingFeeBump = false;
     rollingMinimumFeeRate = 0;
     ++nTransactionsUpdated;
 }
 
 void CTxMemPool::clear() {
     LOCK(cs);
     _clear();
 }
 
 static void CheckInputsAndUpdateCoins(const CTransaction &tx,
                                       CCoinsViewCache &mempoolDuplicate,
                                       const int64_t spendheight) {
     // Not used. CheckTxInputs() should always pass
     TxValidationState dummy_state;
     Amount txfee = Amount::zero();
     bool fCheckResult =
         tx.IsCoinBase() ||
         Consensus::CheckTxInputs(tx, dummy_state, mempoolDuplicate, spendheight,
                                  txfee);
     assert(fCheckResult);
     UpdateCoins(mempoolDuplicate, tx, std::numeric_limits<int>::max());
 }
 
 void CTxMemPool::check(const CCoinsViewCache *pcoins) const {
     LOCK(cs);
     if (nCheckFrequency == 0) {
         return;
     }
 
     if (GetRand(std::numeric_limits<uint32_t>::max()) >= nCheckFrequency) {
         return;
     }
 
     LogPrint(BCLog::MEMPOOL,
              "Checking mempool with %u transactions and %u inputs\n",
              (unsigned int)mapTx.size(), (unsigned int)mapNextTx.size());
 
     uint64_t checkTotal = 0;
     uint64_t innerUsage = 0;
 
     CCoinsViewCache mempoolDuplicate(const_cast<CCoinsViewCache *>(pcoins));
     const int64_t spendheight = GetSpendHeight(mempoolDuplicate);
 
     std::list<const CTxMemPoolEntry *> waitingOnDependants;
     for (indexed_transaction_set::const_iterator it = mapTx.begin();
          it != mapTx.end(); it++) {
         unsigned int i = 0;
         checkTotal += it->GetTxSize();
         innerUsage += it->DynamicMemoryUsage();
         const CTransaction &tx = it->GetTx();
         innerUsage += memusage::DynamicUsage(it->GetMemPoolParentsConst()) +
                       memusage::DynamicUsage(it->GetMemPoolChildrenConst());
         bool fDependsWait = false;
         CTxMemPoolEntry::Parents setParentCheck;
         for (const CTxIn &txin : tx.vin) {
             // Check that every mempool transaction's inputs refer to available
             // coins, or other mempool tx's.
             indexed_transaction_set::const_iterator it2 =
                 mapTx.find(txin.prevout.GetTxId());
             if (it2 != mapTx.end()) {
                 const CTransaction &tx2 = it2->GetTx();
                 assert(tx2.vout.size() > txin.prevout.GetN() &&
                        !tx2.vout[txin.prevout.GetN()].IsNull());
                 fDependsWait = true;
                 setParentCheck.insert(*it2);
             } else {
                 assert(pcoins->HaveCoin(txin.prevout));
             }
             // Check whether its inputs are marked in mapNextTx.
             auto it3 = mapNextTx.find(txin.prevout);
             assert(it3 != mapNextTx.end());
             assert(it3->first == &txin.prevout);
             assert(it3->second == &tx);
             i++;
         }
         auto comp = [](const CTxMemPoolEntry &a,
                        const CTxMemPoolEntry &b) -> bool {
             return a.GetTx().GetId() == b.GetTx().GetId();
         };
         assert(setParentCheck.size() == it->GetMemPoolParentsConst().size());
         assert(std::equal(setParentCheck.begin(), setParentCheck.end(),
                           it->GetMemPoolParentsConst().begin(), comp));
         // Verify ancestor state is correct.
         setEntries setAncestors;
         uint64_t nNoLimit = std::numeric_limits<uint64_t>::max();
         std::string dummy;
         CalculateMemPoolAncestors(*it, setAncestors, nNoLimit, nNoLimit,
                                   nNoLimit, nNoLimit, dummy);
         uint64_t nCountCheck = setAncestors.size() + 1;
         uint64_t nSizeCheck = it->GetTxSize();
         Amount nFeesCheck = it->GetModifiedFee();
         int64_t nSigOpCheck = it->GetSigOpCount();
 
         for (txiter ancestorIt : setAncestors) {
             nSizeCheck += ancestorIt->GetTxSize();
             nFeesCheck += ancestorIt->GetModifiedFee();
             nSigOpCheck += ancestorIt->GetSigOpCount();
         }
 
         assert(it->GetCountWithAncestors() == nCountCheck);
         assert(it->GetSizeWithAncestors() == nSizeCheck);
         assert(it->GetSigOpCountWithAncestors() == nSigOpCheck);
         assert(it->GetModFeesWithAncestors() == nFeesCheck);
 
         // Check children against mapNextTx
         CTxMemPoolEntry::Children setChildrenCheck;
         auto iter = mapNextTx.lower_bound(COutPoint(it->GetTx().GetId(), 0));
         uint64_t child_sizes = 0;
         int64_t child_sigop_counts = 0;
         for (; iter != mapNextTx.end() &&
                iter->first->GetTxId() == it->GetTx().GetId();
              ++iter) {
             txiter childit = mapTx.find(iter->second->GetId());
             // mapNextTx points to in-mempool transactions
             assert(childit != mapTx.end());
             if (setChildrenCheck.insert(*childit).second) {
                 child_sizes += childit->GetTxSize();
                 child_sigop_counts += childit->GetSigOpCount();
             }
         }
         assert(setChildrenCheck.size() == it->GetMemPoolChildrenConst().size());
         assert(std::equal(setChildrenCheck.begin(), setChildrenCheck.end(),
                           it->GetMemPoolChildrenConst().begin(), comp));
         // Also check to make sure size is greater than sum with immediate
         // children. Just a sanity check, not definitive that this calc is
         // correct...
         assert(it->GetSizeWithDescendants() >= child_sizes + it->GetTxSize());
         assert(it->GetSigOpCountWithDescendants() >=
                child_sigop_counts + it->GetSigOpCount());
 
         if (fDependsWait) {
             waitingOnDependants.push_back(&(*it));
         } else {
             CheckInputsAndUpdateCoins(tx, mempoolDuplicate, spendheight);
         }
     }
 
     unsigned int stepsSinceLastRemove = 0;
     while (!waitingOnDependants.empty()) {
         const CTxMemPoolEntry *entry = waitingOnDependants.front();
         waitingOnDependants.pop_front();
         if (!mempoolDuplicate.HaveInputs(entry->GetTx())) {
             waitingOnDependants.push_back(entry);
             stepsSinceLastRemove++;
             assert(stepsSinceLastRemove < waitingOnDependants.size());
         } else {
             CheckInputsAndUpdateCoins(entry->GetTx(), mempoolDuplicate,
                                       spendheight);
             stepsSinceLastRemove = 0;
         }
     }
 
     for (auto it = mapNextTx.cbegin(); it != mapNextTx.cend(); it++) {
         const TxId &txid = it->second->GetId();
         indexed_transaction_set::const_iterator it2 = mapTx.find(txid);
         const CTransaction &tx = it2->GetTx();
         assert(it2 != mapTx.end());
         assert(&tx == it->second);
     }
 
     assert(totalTxSize == checkTotal);
     assert(innerUsage == cachedInnerUsage);
 }
 
 bool CTxMemPool::CompareDepthAndScore(const TxId &txida, const TxId &txidb) {
     LOCK(cs);
     indexed_transaction_set::const_iterator i = mapTx.find(txida);
     if (i == mapTx.end()) {
         return false;
     }
     indexed_transaction_set::const_iterator j = mapTx.find(txidb);
     if (j == mapTx.end()) {
         return true;
     }
     uint64_t counta = i->GetCountWithAncestors();
     uint64_t countb = j->GetCountWithAncestors();
     if (counta == countb) {
         return CompareTxMemPoolEntryByScore()(*i, *j);
     }
     return counta < countb;
 }
 
 namespace {
 class DepthAndScoreComparator {
 public:
     bool
     operator()(const CTxMemPool::indexed_transaction_set::const_iterator &a,
                const CTxMemPool::indexed_transaction_set::const_iterator &b) {
         uint64_t counta = a->GetCountWithAncestors();
         uint64_t countb = b->GetCountWithAncestors();
         if (counta == countb) {
             return CompareTxMemPoolEntryByScore()(*a, *b);
         }
         return counta < countb;
     }
 };
 } // namespace
 
 std::vector<CTxMemPool::indexed_transaction_set::const_iterator>
 CTxMemPool::GetSortedDepthAndScore() const {
     std::vector<indexed_transaction_set::const_iterator> iters;
     AssertLockHeld(cs);
 
     iters.reserve(mapTx.size());
     for (indexed_transaction_set::iterator mi = mapTx.begin();
          mi != mapTx.end(); ++mi) {
         iters.push_back(mi);
     }
 
     std::sort(iters.begin(), iters.end(), DepthAndScoreComparator());
     return iters;
 }
 
 void CTxMemPool::queryHashes(std::vector<uint256> &vtxid) const {
     LOCK(cs);
     auto iters = GetSortedDepthAndScore();
 
     vtxid.clear();
     vtxid.reserve(mapTx.size());
 
     for (auto it : iters) {
         vtxid.push_back(it->GetTx().GetId());
     }
 }
 
 static TxMempoolInfo
 GetInfo(CTxMemPool::indexed_transaction_set::const_iterator it) {
     return TxMempoolInfo{it->GetSharedTx(), it->GetTime(), it->GetFee(),
                          it->GetTxSize(), it->GetModifiedFee() - it->GetFee()};
 }
 
 std::vector<TxMempoolInfo> CTxMemPool::infoAll() const {
     LOCK(cs);
     auto iters = GetSortedDepthAndScore();
 
     std::vector<TxMempoolInfo> ret;
     ret.reserve(mapTx.size());
     for (auto it : iters) {
         ret.push_back(GetInfo(it));
     }
 
     return ret;
 }
 
 CTransactionRef CTxMemPool::get(const TxId &txid) const {
     LOCK(cs);
     indexed_transaction_set::const_iterator i = mapTx.find(txid);
     if (i == mapTx.end()) {
         return nullptr;
     }
 
     return i->GetSharedTx();
 }
 
 TxMempoolInfo CTxMemPool::info(const TxId &txid) const {
     LOCK(cs);
     indexed_transaction_set::const_iterator i = mapTx.find(txid);
     if (i == mapTx.end()) {
         return TxMempoolInfo();
     }
 
     return GetInfo(i);
 }
 
 CFeeRate CTxMemPool::estimateFee() const {
     LOCK(cs);
 
     uint64_t maxMempoolSize =
         gArgs.GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000;
     // minerPolicy uses recent blocks to figure out a reasonable fee.  This
     // may disagree with the rollingMinimumFeerate under certain scenarios
     // where the mempool  increases rapidly, or blocks are being mined which
     // do not contain propagated transactions.
     return std::max(::minRelayTxFee, GetMinFee(maxMempoolSize));
 }
 
 void CTxMemPool::PrioritiseTransaction(const TxId &txid,
                                        const Amount nFeeDelta) {
     {
         LOCK(cs);
         Amount &delta = mapDeltas[txid];
         delta += nFeeDelta;
         txiter it = mapTx.find(txid);
         if (it != mapTx.end()) {
             mapTx.modify(it, update_fee_delta(delta));
             // Now update all ancestors' modified fees with descendants
             setEntries setAncestors;
             uint64_t nNoLimit = std::numeric_limits<uint64_t>::max();
             std::string dummy;
             CalculateMemPoolAncestors(*it, setAncestors, nNoLimit, nNoLimit,
                                       nNoLimit, nNoLimit, dummy, false);
             for (txiter ancestorIt : setAncestors) {
                 mapTx.modify(ancestorIt,
                              update_descendant_state(0, nFeeDelta, 0, 0));
             }
 
             // Now update all descendants' modified fees with ancestors
             setEntries setDescendants;
             CalculateDescendants(it, setDescendants);
             setDescendants.erase(it);
             for (txiter descendantIt : setDescendants) {
                 mapTx.modify(descendantIt,
                              update_ancestor_state(0, nFeeDelta, 0, 0));
             }
             ++nTransactionsUpdated;
         }
     }
     LogPrintf("PrioritiseTransaction: %s fee += %s\n", txid.ToString(),
               FormatMoney(nFeeDelta));
 }
 
 void CTxMemPool::ApplyDelta(const TxId &txid, Amount &nFeeDelta) const {
     AssertLockHeld(cs);
     std::map<TxId, Amount>::const_iterator pos = mapDeltas.find(txid);
     if (pos == mapDeltas.end()) {
         return;
     }
 
     nFeeDelta += pos->second;
 }
 
 void CTxMemPool::ClearPrioritisation(const TxId &txid) {
     AssertLockHeld(cs);
     mapDeltas.erase(txid);
 }
 
 const CTransaction *CTxMemPool::GetConflictTx(const COutPoint &prevout) const {
     const auto it = mapNextTx.find(prevout);
     return it == mapNextTx.end() ? nullptr : it->second;
 }
 
 std::optional<CTxMemPool::txiter> CTxMemPool::GetIter(const TxId &txid) const {
     auto it = mapTx.find(txid);
     if (it != mapTx.end()) {
         return it;
     }
     return std::optional<txiter>{std::nullopt};
 }
 
 CTxMemPool::setEntries
 CTxMemPool::GetIterSet(const std::set<TxId> &txids) const {
     CTxMemPool::setEntries ret;
     for (const auto &txid : txids) {
         const auto mi = GetIter(txid);
         if (mi) {
             ret.insert(*mi);
         }
     }
     return ret;
 }
 
 bool CTxMemPool::HasNoInputsOf(const CTransaction &tx) const {
     for (const CTxIn &in : tx.vin) {
         if (exists(in.prevout.GetTxId())) {
             return false;
         }
     }
 
     return true;
 }
 
 CCoinsViewMemPool::CCoinsViewMemPool(CCoinsView *baseIn,
                                      const CTxMemPool &mempoolIn)
     : CCoinsViewBacked(baseIn), mempool(mempoolIn) {}
 
 bool CCoinsViewMemPool::GetCoin(const COutPoint &outpoint, Coin &coin) const {
     // If an entry in the mempool exists, always return that one, as it's
     // guaranteed to never conflict with the underlying cache, and it cannot
     // have pruned entries (as it contains full) transactions. First checking
     // the underlying cache risks returning a pruned entry instead.
     CTransactionRef ptx = mempool.get(outpoint.GetTxId());
     if (ptx) {
         if (outpoint.GetN() < ptx->vout.size()) {
             coin = Coin(ptx->vout[outpoint.GetN()], MEMPOOL_HEIGHT, false);
             return true;
         }
         return false;
     }
     return base->GetCoin(outpoint, coin);
 }
 
 size_t CTxMemPool::DynamicMemoryUsage() const {
     LOCK(cs);
     // Estimate the overhead of mapTx to be 12 pointers + an allocation, as no
     // exact formula for boost::multi_index_contained is implemented.
     return memusage::MallocUsage(sizeof(CTxMemPoolEntry) +
                                  12 * sizeof(void *)) *
                mapTx.size() +
            memusage::DynamicUsage(mapNextTx) +
            memusage::DynamicUsage(mapDeltas) +
            memusage::DynamicUsage(vTxHashes) + cachedInnerUsage;
 }
 
 void CTxMemPool::RemoveUnbroadcastTx(const TxId &txid, const bool unchecked) {
     LOCK(cs);
 
     if (m_unbroadcast_txids.erase(txid)) {
         LogPrint(
             BCLog::MEMPOOL, "Removed %i from set of unbroadcast txns%s\n",
             txid.GetHex(),
             (unchecked ? " before confirmation that txn was sent out" : ""));
     }
 }
 
 void CTxMemPool::RemoveStaged(setEntries &stage, bool updateDescendants,
                               MemPoolRemovalReason reason) {
     AssertLockHeld(cs);
     UpdateForRemoveFromMempool(stage, updateDescendants);
     for (txiter it : stage) {
         removeUnchecked(it, reason);
     }
 }
 
 int CTxMemPool::Expire(std::chrono::seconds time) {
     AssertLockHeld(cs);
     indexed_transaction_set::index<entry_time>::type::iterator it =
         mapTx.get<entry_time>().begin();
     setEntries toremove;
     while (it != mapTx.get<entry_time>().end() && it->GetTime() < time) {
         toremove.insert(mapTx.project<0>(it));
         it++;
     }
 
     setEntries stage;
     for (txiter removeit : toremove) {
         CalculateDescendants(removeit, stage);
     }
 
     RemoveStaged(stage, false, MemPoolRemovalReason::EXPIRY);
     return stage.size();
 }
 
 void CTxMemPool::LimitSize(size_t limit, std::chrono::seconds age) {
     int expired = Expire(GetTime<std::chrono::seconds>() - age);
     if (expired != 0) {
         LogPrint(BCLog::MEMPOOL,
                  "Expired %i transactions from the memory pool\n", expired);
     }
 
     std::vector<COutPoint> vNoSpendsRemaining;
     TrimToSize(limit, &vNoSpendsRemaining);
     for (const COutPoint &removed : vNoSpendsRemaining) {
         ::ChainstateActive().CoinsTip().Uncache(removed);
     }
 }
 
 void CTxMemPool::addUnchecked(const CTxMemPoolEntry &entry) {
     setEntries setAncestors;
     uint64_t nNoLimit = std::numeric_limits<uint64_t>::max();
     std::string dummy;
     CalculateMemPoolAncestors(entry, setAncestors, nNoLimit, nNoLimit, nNoLimit,
                               nNoLimit, dummy);
     return addUnchecked(entry, setAncestors);
 }
 
 void CTxMemPool::UpdateChild(txiter entry, txiter child, bool add) {
     AssertLockHeld(cs);
     CTxMemPoolEntry::Children s;
     if (add && entry->GetMemPoolChildren().insert(*child).second) {
         cachedInnerUsage += memusage::IncrementalDynamicUsage(s);
     } else if (!add && entry->GetMemPoolChildren().erase(*child)) {
         cachedInnerUsage -= memusage::IncrementalDynamicUsage(s);
     }
 }
 
 void CTxMemPool::UpdateParent(txiter entry, txiter parent, bool add) {
     AssertLockHeld(cs);
     CTxMemPoolEntry::Parents s;
     if (add && entry->GetMemPoolParents().insert(*parent).second) {
         cachedInnerUsage += memusage::IncrementalDynamicUsage(s);
     } else if (!add && entry->GetMemPoolParents().erase(*parent)) {
         cachedInnerUsage -= memusage::IncrementalDynamicUsage(s);
     }
 }
 
 CFeeRate CTxMemPool::GetMinFee(size_t sizelimit) const {
     LOCK(cs);
     if (!blockSinceLastRollingFeeBump || rollingMinimumFeeRate == 0) {
         return CFeeRate(int64_t(ceill(rollingMinimumFeeRate)) * SATOSHI);
     }
 
     int64_t time = GetTime();
     if (time > lastRollingFeeUpdate + 10) {
         double halflife = ROLLING_FEE_HALFLIFE;
         if (DynamicMemoryUsage() < sizelimit / 4) {
             halflife /= 4;
         } else if (DynamicMemoryUsage() < sizelimit / 2) {
             halflife /= 2;
         }
 
         rollingMinimumFeeRate =
             rollingMinimumFeeRate /
             pow(2.0, (time - lastRollingFeeUpdate) / halflife);
         lastRollingFeeUpdate = time;
     }
     return CFeeRate(int64_t(ceill(rollingMinimumFeeRate)) * SATOSHI);
 }
 
 void CTxMemPool::trackPackageRemoved(const CFeeRate &rate) {
     AssertLockHeld(cs);
     if ((rate.GetFeePerK() / SATOSHI) > rollingMinimumFeeRate) {
         rollingMinimumFeeRate = rate.GetFeePerK() / SATOSHI;
         blockSinceLastRollingFeeBump = false;
     }
 }
 
 void CTxMemPool::TrimToSize(size_t sizelimit,
                             std::vector<COutPoint> *pvNoSpendsRemaining) {
     AssertLockHeld(cs);
 
     unsigned nTxnRemoved = 0;
     CFeeRate maxFeeRateRemoved(Amount::zero());
     while (!mapTx.empty() && DynamicMemoryUsage() > sizelimit) {
         indexed_transaction_set::index<descendant_score>::type::iterator it =
             mapTx.get<descendant_score>().begin();
 
         // We set the new mempool min fee to the feerate of the removed set,
         // plus the "minimum reasonable fee rate" (ie some value under which we
         // consider txn to have 0 fee). This way, we don't allow txn to enter
         // mempool with feerate equal to txn which were removed with no block in
         // between.
         CFeeRate removed(it->GetModFeesWithDescendants(),
                          it->GetVirtualSizeWithDescendants());
         removed += MEMPOOL_FULL_FEE_INCREMENT;
 
         trackPackageRemoved(removed);
         maxFeeRateRemoved = std::max(maxFeeRateRemoved, removed);
 
         setEntries stage;
         CalculateDescendants(mapTx.project<0>(it), stage);
         nTxnRemoved += stage.size();
 
         std::vector<CTransaction> txn;
         if (pvNoSpendsRemaining) {
             txn.reserve(stage.size());
             for (txiter iter : stage) {
                 txn.push_back(iter->GetTx());
             }
         }
         RemoveStaged(stage, false, MemPoolRemovalReason::SIZELIMIT);
         if (pvNoSpendsRemaining) {
             for (const CTransaction &tx : txn) {
                 for (const CTxIn &txin : tx.vin) {
                     if (exists(txin.prevout.GetTxId())) {
                         continue;
                     }
                     pvNoSpendsRemaining->push_back(txin.prevout);
                 }
             }
         }
     }
 
     if (maxFeeRateRemoved > CFeeRate(Amount::zero())) {
         LogPrint(BCLog::MEMPOOL,
                  "Removed %u txn, rolling minimum fee bumped to %s\n",
                  nTxnRemoved, maxFeeRateRemoved.ToString());
     }
 }
 
 uint64_t CTxMemPool::CalculateDescendantMaximum(txiter entry) const {
     // find parent with highest descendant count
     std::vector<txiter> candidates;
     setEntries counted;
     candidates.push_back(entry);
     uint64_t maximum = 0;
     while (candidates.size()) {
         txiter candidate = candidates.back();
         candidates.pop_back();
         if (!counted.insert(candidate).second) {
             continue;
         }
         const CTxMemPoolEntry::Parents &parents =
             candidate->GetMemPoolParentsConst();
         if (parents.size() == 0) {
             maximum = std::max(maximum, candidate->GetCountWithDescendants());
         } else {
             for (const CTxMemPoolEntry &i : parents) {
                 candidates.push_back(mapTx.iterator_to(i));
             }
         }
     }
     return maximum;
 }
 
 void CTxMemPool::GetTransactionAncestry(const TxId &txid, size_t &ancestors,
                                         size_t &descendants) const {
     LOCK(cs);
     auto it = mapTx.find(txid);
     ancestors = descendants = 0;
     if (it != mapTx.end()) {
         ancestors = it->GetCountWithAncestors();
         descendants = CalculateDescendantMaximum(it);
     }
 }
 
 bool CTxMemPool::IsLoaded() const {
     LOCK(cs);
     return m_is_loaded;
 }
 
 void CTxMemPool::SetIsLoaded(bool loaded) {
     LOCK(cs);
     m_is_loaded = loaded;
 }
 
 /** Maximum bytes for transactions to store for processing during reorg */
 static const size_t MAX_DISCONNECTED_TX_POOL_SIZE = 20 * DEFAULT_MAX_BLOCK_SIZE;
 
 void DisconnectedBlockTransactions::addForBlock(
     const std::vector<CTransactionRef> &vtx, CTxMemPool &pool) {
     AssertLockHeld(pool.cs);
     for (const auto &tx : reverse_iterate(vtx)) {
         // If we already added it, just skip.
         auto it = queuedTx.find(tx->GetId());
         if (it != queuedTx.end()) {
             continue;
         }
 
         // Insert the transaction into the pool.
         addTransaction(tx);
 
         // Fill in the set of parents.
         std::unordered_set<TxId, SaltedTxIdHasher> parents;
         for (const CTxIn &in : tx->vin) {
             parents.insert(in.prevout.GetTxId());
         }
 
         // In order to make sure we keep things in topological order, we check
         // if we already know of the parent of the current transaction. If so,
         // we remove them from the set and then add them back.
         while (parents.size() > 0) {
             std::unordered_set<TxId, SaltedTxIdHasher> worklist(
                 std::move(parents));
             parents.clear();
 
             for (const TxId &txid : worklist) {
                 // If we do not have that txid in the set, nothing needs to be
                 // done.
                 auto pit = queuedTx.find(txid);
                 if (pit == queuedTx.end()) {
                     continue;
                 }
 
                 // We have parent in our set, we reinsert them at the right
                 // position.
                 const CTransactionRef ptx = *pit;
                 queuedTx.erase(pit);
                 queuedTx.insert(ptx);
 
                 // And we make sure ancestors are covered.
                 for (const CTxIn &in : ptx->vin) {
                     parents.insert(in.prevout.GetTxId());
                 }
             }
         }
     }
 
     // Keep the size under control.
     while (DynamicMemoryUsage() > MAX_DISCONNECTED_TX_POOL_SIZE) {
         // Drop the earliest entry, and remove its children from the
         // mempool.
         auto it = queuedTx.get<insertion_order>().begin();
         pool.removeRecursive(**it, MemPoolRemovalReason::REORG);
         removeEntry(it);
     }
 }
 
 void DisconnectedBlockTransactions::importMempool(CTxMemPool &pool) {
     AssertLockHeld(pool.cs);
     // addForBlock's algorithm sorts a vector of transactions back into
     // topological order. We use it in a separate object to create a valid
     // ordering of all mempool transactions, which we then splice in front of
     // the current queuedTx. This results in a valid sequence of transactions to
     // be reprocessed in updateMempoolForReorg.
 
     // We create vtx in order of the entry_time index to facilitate for
     // addForBlocks (which iterates in reverse order), as vtx probably end in
     // the correct ordering for queuedTx.
     std::vector<CTransactionRef> vtx;
 
     vtx.reserve(pool.mapTx.size());
     for (const CTxMemPoolEntry &e : pool.mapTx.get<entry_time>()) {
         vtx.push_back(e.GetSharedTx());
     }
     pool.clear();
 
     // Use addForBlocks to sort the transactions and then splice them in front
     // of queuedTx
     DisconnectedBlockTransactions orderedTxnPool;
     orderedTxnPool.addForBlock(vtx, pool);
     cachedInnerUsage += orderedTxnPool.cachedInnerUsage;
     queuedTx.get<insertion_order>().splice(
         queuedTx.get<insertion_order>().begin(),
         orderedTxnPool.queuedTx.get<insertion_order>());
 
     // We limit memory usage because we can't know if more blocks will be
     // disconnected
     while (DynamicMemoryUsage() > MAX_DISCONNECTED_TX_POOL_SIZE) {
         // Drop the earliest entry which, by definition, has no children
         removeEntry(queuedTx.get<insertion_order>().begin());
     }
 }
 
 void DisconnectedBlockTransactions::updateMempoolForReorg(const Config &config,
                                                           bool fAddToMempool,
                                                           CTxMemPool &pool) {
     AssertLockHeld(cs_main);
     AssertLockHeld(pool.cs);
     std::vector<TxId> txidsUpdate;
 
     // disconnectpool's insertion_order index sorts the entries from oldest to
     // newest, but the oldest entry will be the last tx from the latest mined
     // block that was disconnected.
     // Iterate disconnectpool in reverse, so that we add transactions back to
     // the mempool starting with the earliest transaction that had been
     // previously seen in a block.
     for (const CTransactionRef &tx :
          reverse_iterate(queuedTx.get<insertion_order>())) {
         // ignore validation errors in resurrected transactions
         TxValidationState stateDummy;
         if (!fAddToMempool || tx->IsCoinBase() ||
             !AcceptToMemoryPool(config, pool, stateDummy, tx,
                                 true /* bypass_limits */,
                                 Amount::zero() /* nAbsurdFee */)) {
             // If the transaction doesn't make it in to the mempool, remove any
             // transactions that depend on it (which would now be orphans).
             pool.removeRecursive(*tx, MemPoolRemovalReason::REORG);
         } else if (pool.exists(tx->GetId())) {
             txidsUpdate.push_back(tx->GetId());
         }
     }
 
     queuedTx.clear();
 
     // AcceptToMemoryPool/addUnchecked all assume that new mempool entries have
     // no in-mempool children, which is generally not true when adding
     // previously-confirmed transactions back to the mempool.
     // UpdateTransactionsFromBlock finds descendants of any transactions in the
     // disconnectpool that were added back and cleans up the mempool state.
     pool.UpdateTransactionsFromBlock(txidsUpdate);
 
     // We also need to remove any now-immature transactions
     pool.removeForReorg(config, &::ChainstateActive().CoinsTip(),
                         ::ChainActive().Tip()->nHeight + 1,
                         STANDARD_LOCKTIME_VERIFY_FLAGS);
 
     // Re-limit mempool size, in case we added any transactions
     pool.LimitSize(gArgs.GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) *
                        1000000,
                    std::chrono::hours{
                        gArgs.GetArg("-mempoolexpiry", DEFAULT_MEMPOOL_EXPIRY)});
 }
 
 CTxMemPool::EpochGuard CTxMemPool::GetFreshEpoch() const {
     return EpochGuard(*this);
 }
 
 CTxMemPool::EpochGuard::EpochGuard(const CTxMemPool &in) : pool(in) {
     assert(!pool.m_has_epoch_guard);
     ++pool.m_epoch;
     pool.m_has_epoch_guard = true;
 }
 
 CTxMemPool::EpochGuard::~EpochGuard() {
     // prevents stale results being used
     ++pool.m_epoch;
     pool.m_has_epoch_guard = false;
 }
diff --git a/src/txmempool.h b/src/txmempool.h
index d0eab9b54..da0ee3875 100644
--- a/src/txmempool.h
+++ b/src/txmempool.h
@@ -1,1069 +1,1083 @@
 // Copyright (c) 2009-2010 Satoshi Nakamoto
 // Copyright (c) 2009-2016 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #ifndef BITCOIN_TXMEMPOOL_H
 #define BITCOIN_TXMEMPOOL_H
 
 #include <amount.h>
 #include <coins.h>
 #include <core_memusage.h>
 #include <indirectmap.h>
 #include <primitives/transaction.h>
 #include <salteduint256hasher.h>
 #include <sync.h>
 
 #include <boost/multi_index/hashed_index.hpp>
 #include <boost/multi_index/ordered_index.hpp>
 #include <boost/multi_index/sequenced_index.hpp>
 #include <boost/multi_index_container.hpp>
 
 #include <atomic>
 #include <map>
 #include <optional>
 #include <set>
 #include <string>
 #include <utility>
 #include <vector>
 
 class CBlockIndex;
 class Config;
 
 extern RecursiveMutex cs_main;
 
 /**
  * Fake height value used in Coins to signify they are only in the memory
  * pool(since 0.8)
  */
 static const uint32_t MEMPOOL_HEIGHT = 0x7FFFFFFF;
 
 struct LockPoints {
     // Will be set to the blockchain height and median time past values that
     // would be necessary to satisfy all relative locktime constraints (BIP68)
     // of this tx given our view of block chain history
     int height;
     int64_t time;
     // As long as the current chain descends from the highest height block
     // containing one of the inputs used in the calculation, then the cached
     // values are still valid even after a reorg.
     CBlockIndex *maxInputBlock;
 
     LockPoints() : height(0), time(0), maxInputBlock(nullptr) {}
 };
 
 struct CompareIteratorById {
     // SFINAE for T where T is either a pointer type (e.g., a txiter) or a
     // reference_wrapper<T> (e.g. a wrapped CTxMemPoolEntry&)
     template <typename T>
     bool operator()(const std::reference_wrapper<T> &a,
                     const std::reference_wrapper<T> &b) const {
         return a.get().GetTx().GetId() < b.get().GetTx().GetId();
     }
     template <typename T> bool operator()(const T &a, const T &b) const {
         return a->GetTx().GetId() < b->GetTx().GetId();
     }
 };
 
 /** \class CTxMemPoolEntry
  *
  * CTxMemPoolEntry stores data about the corresponding transaction, as well as
  * data about all in-mempool transactions that depend on the transaction
  * ("descendant" transactions).
  *
  * When a new entry is added to the mempool, we update the descendant state
  * (nCountWithDescendants, nSizeWithDescendants, and nModFeesWithDescendants)
  * for all ancestors of the newly added transaction.
  */
 
 class CTxMemPoolEntry {
 public:
     typedef std::reference_wrapper<const CTxMemPoolEntry> CTxMemPoolEntryRef;
     // two aliases, should the types ever diverge
     typedef std::set<CTxMemPoolEntryRef, CompareIteratorById> Parents;
     typedef std::set<CTxMemPoolEntryRef, CompareIteratorById> Children;
 
 private:
     const CTransactionRef tx;
     mutable Parents m_parents;
     mutable Children m_children;
     //! Cached to avoid expensive parent-transaction lookups
     const Amount nFee;
     //! ... and avoid recomputing tx size
     const size_t nTxSize;
     //! ... and total memory usage
     const size_t nUsageSize;
     //! Local time when entering the mempool
     const int64_t nTime;
     //! Chain height when entering the mempool
     const unsigned int entryHeight;
     //! keep track of transactions that spend a coinbase
     const bool spendsCoinbase;
     /**
      * Total sigop plus P2SH sigops count.
      * After the sigchecks activation we repurpose the 'sigops' tracking in
      * mempool/mining to actually track sigchecks instead. (Proper SigOps will
      * not need to be counted any more since it's getting deactivated.)
      */
     const int64_t sigOpCount;
     //! Used for determining the priority of the transaction for mining in a
     //! block
     Amount feeDelta;
     //! Track the height and time at which tx was final
     LockPoints lockPoints;
 
     // Information about descendants of this transaction that are in the
     // mempool; if we remove this transaction we must remove all of these
     // descendants as well.
     //! number of descendant transactions
     uint64_t nCountWithDescendants;
     //! ... and size
     uint64_t nSizeWithDescendants;
     //! ... and total fees (all including us)
     Amount nModFeesWithDescendants;
     //! ... and sigop count
     int64_t nSigOpCountWithDescendants;
 
     // Analogous statistics for ancestor transactions
     uint64_t nCountWithAncestors;
     uint64_t nSizeWithAncestors;
     Amount nModFeesWithAncestors;
     int64_t nSigOpCountWithAncestors;
 
 public:
     CTxMemPoolEntry(const CTransactionRef &_tx, const Amount _nFee,
                     int64_t _nTime, unsigned int _entryHeight,
                     bool spendsCoinbase, int64_t _nSigOpCount, LockPoints lp);
 
     const CTransaction &GetTx() const { return *this->tx; }
     CTransactionRef GetSharedTx() const { return this->tx; }
     const Amount GetFee() const { return nFee; }
     size_t GetTxSize() const { return nTxSize; }
     size_t GetTxVirtualSize() const;
 
     std::chrono::seconds GetTime() const { return std::chrono::seconds{nTime}; }
     unsigned int GetHeight() const { return entryHeight; }
     int64_t GetSigOpCount() const { return sigOpCount; }
     Amount GetModifiedFee() const { return nFee + feeDelta; }
     size_t DynamicMemoryUsage() const { return nUsageSize; }
     const LockPoints &GetLockPoints() const { return lockPoints; }
 
     // Adjusts the descendant state.
     void UpdateDescendantState(int64_t modifySize, Amount modifyFee,
                                int64_t modifyCount, int64_t modifySigOpCount);
     // Adjusts the ancestor state
     void UpdateAncestorState(int64_t modifySize, Amount modifyFee,
                              int64_t modifyCount, int64_t modifySigOps);
     // Updates the fee delta used for mining priority score, and the
     // modified fees with descendants.
     void UpdateFeeDelta(Amount feeDelta);
     // Update the LockPoints after a reorg
     void UpdateLockPoints(const LockPoints &lp);
 
     uint64_t GetCountWithDescendants() const { return nCountWithDescendants; }
     uint64_t GetSizeWithDescendants() const { return nSizeWithDescendants; }
     uint64_t GetVirtualSizeWithDescendants() const;
     Amount GetModFeesWithDescendants() const { return nModFeesWithDescendants; }
     int64_t GetSigOpCountWithDescendants() const {
         return nSigOpCountWithDescendants;
     }
 
     bool GetSpendsCoinbase() const { return spendsCoinbase; }
 
     uint64_t GetCountWithAncestors() const { return nCountWithAncestors; }
     uint64_t GetSizeWithAncestors() const { return nSizeWithAncestors; }
     uint64_t GetVirtualSizeWithAncestors() const;
     Amount GetModFeesWithAncestors() const { return nModFeesWithAncestors; }
     int64_t GetSigOpCountWithAncestors() const {
         return nSigOpCountWithAncestors;
     }
 
     const Parents &GetMemPoolParentsConst() const { return m_parents; }
     const Children &GetMemPoolChildrenConst() const { return m_children; }
     Parents &GetMemPoolParents() const { return m_parents; }
     Children &GetMemPoolChildren() const { return m_children; }
 
     //! Index in mempool's vTxHashes
     mutable size_t vTxHashesIdx;
     //! epoch when last touched, useful for graph algorithms
     mutable uint64_t m_epoch;
 };
 
 // Helpers for modifying CTxMemPool::mapTx, which is a boost multi_index.
 struct update_descendant_state {
     update_descendant_state(int64_t _modifySize, Amount _modifyFee,
                             int64_t _modifyCount, int64_t _modifySigOpCount)
         : modifySize(_modifySize), modifyFee(_modifyFee),
           modifyCount(_modifyCount), modifySigOpCount(_modifySigOpCount) {}
 
     void operator()(CTxMemPoolEntry &e) {
         e.UpdateDescendantState(modifySize, modifyFee, modifyCount,
                                 modifySigOpCount);
     }
 
 private:
     int64_t modifySize;
     Amount modifyFee;
     int64_t modifyCount;
     int64_t modifySigOpCount;
 };
 
 struct update_ancestor_state {
     update_ancestor_state(int64_t _modifySize, Amount _modifyFee,
                           int64_t _modifyCount, int64_t _modifySigOpCount)
         : modifySize(_modifySize), modifyFee(_modifyFee),
           modifyCount(_modifyCount), modifySigOpCount(_modifySigOpCount) {}
 
     void operator()(CTxMemPoolEntry &e) {
         e.UpdateAncestorState(modifySize, modifyFee, modifyCount,
                               modifySigOpCount);
     }
 
 private:
     int64_t modifySize;
     Amount modifyFee;
     int64_t modifyCount;
     int64_t modifySigOpCount;
 };
 
 struct update_fee_delta {
     explicit update_fee_delta(Amount _feeDelta) : feeDelta(_feeDelta) {}
 
     void operator()(CTxMemPoolEntry &e) { e.UpdateFeeDelta(feeDelta); }
 
 private:
     Amount feeDelta;
 };
 
 struct update_lock_points {
     explicit update_lock_points(const LockPoints &_lp) : lp(_lp) {}
 
     void operator()(CTxMemPoolEntry &e) { e.UpdateLockPoints(lp); }
 
 private:
     const LockPoints &lp;
 };
 
 // extracts a transaction id from CTxMemPoolEntry or CTransactionRef
 struct mempoolentry_txid {
     typedef TxId result_type;
     result_type operator()(const CTxMemPoolEntry &entry) const {
         return entry.GetTx().GetId();
     }
 
     result_type operator()(const CTransactionRef &tx) const {
         return tx->GetId();
     }
 };
 
 /** \class CompareTxMemPoolEntryByDescendantScore
  *
  *  Sort an entry by max(score/size of entry's tx, score/size with all
  * descendants).
  */
 class CompareTxMemPoolEntryByDescendantScore {
 public:
     bool operator()(const CTxMemPoolEntry &a, const CTxMemPoolEntry &b) const {
         double a_mod_fee, a_size, b_mod_fee, b_size;
 
         GetModFeeAndSize(a, a_mod_fee, a_size);
         GetModFeeAndSize(b, b_mod_fee, b_size);
 
         // Avoid division by rewriting (a/b > c/d) as (a*d > c*b).
         double f1 = a_mod_fee * b_size;
         double f2 = a_size * b_mod_fee;
 
         if (f1 == f2) {
             return a.GetTime() >= b.GetTime();
         }
         return f1 < f2;
     }
 
     // Return the fee/size we're using for sorting this entry.
     void GetModFeeAndSize(const CTxMemPoolEntry &a, double &mod_fee,
                           double &size) const {
         // Compare feerate with descendants to feerate of the transaction, and
         // return the fee/size for the max.
         double f1 =
             a.GetVirtualSizeWithDescendants() * (a.GetModifiedFee() / SATOSHI);
         double f2 =
             a.GetTxVirtualSize() * (a.GetModFeesWithDescendants() / SATOSHI);
 
         if (f2 > f1) {
             mod_fee = a.GetModFeesWithDescendants() / SATOSHI;
             size = a.GetVirtualSizeWithDescendants();
         } else {
             mod_fee = a.GetModifiedFee() / SATOSHI;
             size = a.GetTxVirtualSize();
         }
     }
 };
 
 /** \class CompareTxMemPoolEntryByScore
  *
  *  Sort by feerate of entry (fee/size) in descending order
  *  This is only used for transaction relay, so we use GetFee()
  *  instead of GetModifiedFee() to avoid leaking prioritization
  *  information via the sort order.
  */
 class CompareTxMemPoolEntryByScore {
 public:
     bool operator()(const CTxMemPoolEntry &a, const CTxMemPoolEntry &b) const {
         double f1 = b.GetTxSize() * (a.GetFee() / SATOSHI);
         double f2 = a.GetTxSize() * (b.GetFee() / SATOSHI);
         if (f1 == f2) {
             return b.GetTx().GetId() < a.GetTx().GetId();
         }
         return f1 > f2;
     }
 };
 
 class CompareTxMemPoolEntryByEntryTime {
 public:
     bool operator()(const CTxMemPoolEntry &a, const CTxMemPoolEntry &b) const {
         return a.GetTime() < b.GetTime();
     }
 };
 
 /** \class CompareTxMemPoolEntryByAncestorScore
  *
  *  Sort an entry by min(score/size of entry's tx, score/size with all
  * ancestors).
  */
 class CompareTxMemPoolEntryByAncestorFee {
 public:
     template <typename T> bool operator()(const T &a, const T &b) const {
         double a_mod_fee, a_size, b_mod_fee, b_size;
 
         GetModFeeAndSize(a, a_mod_fee, a_size);
         GetModFeeAndSize(b, b_mod_fee, b_size);
 
         // Avoid division by rewriting (a/b > c/d) as (a*d > c*b).
         double f1 = a_mod_fee * b_size;
         double f2 = a_size * b_mod_fee;
 
         if (f1 == f2) {
             return a.GetTx().GetId() < b.GetTx().GetId();
         }
         return f1 > f2;
     }
 
     // Return the fee/size we're using for sorting this entry.
     template <typename T>
     void GetModFeeAndSize(const T &a, double &mod_fee, double &size) const {
         // Compare feerate with ancestors to feerate of the transaction, and
         // return the fee/size for the min.
         double f1 =
             a.GetVirtualSizeWithAncestors() * (a.GetModifiedFee() / SATOSHI);
         double f2 =
             a.GetTxVirtualSize() * (a.GetModFeesWithAncestors() / SATOSHI);
 
         if (f1 > f2) {
             mod_fee = a.GetModFeesWithAncestors() / SATOSHI;
             size = a.GetVirtualSizeWithAncestors();
         } else {
             mod_fee = a.GetModifiedFee() / SATOSHI;
             size = a.GetTxVirtualSize();
         }
     }
 };
 
 // Multi_index tag names
 struct descendant_score {};
 struct entry_time {};
 struct ancestor_score {};
 
 /**
  * Information about a mempool transaction.
  */
 struct TxMempoolInfo {
     /** The transaction itself */
     CTransactionRef tx;
 
     /** Time the transaction entered the mempool. */
     std::chrono::seconds m_time;
 
     /** Fee of the transaction. */
     Amount fee;
 
     /** Virtual size of the transaction. */
     size_t vsize;
 
     /** The fee delta. */
     Amount nFeeDelta;
 };
 
 /**
  * Reason why a transaction was removed from the mempool, this is passed to the
  * notification signal.
  */
 enum class MemPoolRemovalReason {
     //! Expired from mempool
     EXPIRY,
     //! Removed in size limiting
     SIZELIMIT,
     //! Removed for reorganization
     REORG,
     //! Removed for block
     BLOCK,
     //! Removed for conflict with in-block transaction
     CONFLICT,
     //! Removed for replacement
     REPLACED
 };
 
 class SaltedTxIdHasher : private SaltedUint256Hasher {
 public:
     SaltedTxIdHasher() : SaltedUint256Hasher() {}
 
     size_t operator()(const TxId &txid) const { return hash(txid); }
 };
 
 /**
  * CTxMemPool stores valid-according-to-the-current-best-chain transactions that
  * may be included in the next block.
  *
  * Transactions are added when they are seen on the network (or created by the
  * local node), but not all transactions seen are added to the pool. For
  * example, the following new transactions will not be added to the mempool:
  * - a transaction which doesn't meet the minimum fee requirements.
  * - a new transaction that double-spends an input of a transaction already in
  * the pool where the new transaction does not meet the Replace-By-Fee
  * requirements as defined in BIP 125.
  * - a non-standard transaction.
  *
  * CTxMemPool::mapTx, and CTxMemPoolEntry bookkeeping:
  *
  * mapTx is a boost::multi_index that sorts the mempool on 4 criteria:
  * - transaction hash
  * - descendant feerate [we use max(feerate of tx, feerate of tx with all
  * descendants)]
  * - time in mempool
  * - ancestor feerate [we use min(feerate of tx, feerate of tx with all
  * unconfirmed ancestors)]
  *
  * Note: the term "descendant" refers to in-mempool transactions that depend on
  * this one, while "ancestor" refers to in-mempool transactions that a given
  * transaction depends on.
  *
  * In order for the feerate sort to remain correct, we must update transactions
  * in the mempool when new descendants arrive. To facilitate this, we track the
  * set of in-mempool direct parents and direct children in mapLinks. Within each
  * CTxMemPoolEntry, we track the size and fees of all descendants.
  *
  * Usually when a new transaction is added to the mempool, it has no in-mempool
  * children (because any such children would be an orphan). So in
  * addUnchecked(), we:
  * - update a new entry's setMemPoolParents to include all in-mempool parents
  * - update the new entry's direct parents to include the new tx as a child
  * - update all ancestors of the transaction to include the new tx's size/fee
  *
  * When a transaction is removed from the mempool, we must:
  * - update all in-mempool parents to not track the tx in setMemPoolChildren
  * - update all ancestors to not include the tx's size/fees in descendant state
  * - update all in-mempool children to not include it as a parent
  *
  * These happen in UpdateForRemoveFromMempool(). (Note that when removing a
  * transaction along with its descendants, we must calculate that set of
  * transactions to be removed before doing the removal, or else the mempool can
  * be in an inconsistent state where it's impossible to walk the ancestors of a
  * transaction.)
  *
  * In the event of a reorg, the assumption that a newly added tx has no
  * in-mempool children is false.  In particular, the mempool is in an
  * inconsistent state while new transactions are being added, because there may
  * be descendant transactions of a tx coming from a disconnected block that are
  * unreachable from just looking at transactions in the mempool (the linking
  * transactions may also be in the disconnected block, waiting to be added).
  * Because of this, there's not much benefit in trying to search for in-mempool
  * children in addUnchecked(). Instead, in the special case of transactions
  * being added from a disconnected block, we require the caller to clean up the
  * state, to account for in-mempool, out-of-block descendants for all the
  * in-block transactions by calling UpdateTransactionsFromBlock(). Note that
  * until this is called, the mempool state is not consistent, and in particular
  * mapLinks may not be correct (and therefore functions like
  * CalculateMemPoolAncestors() and CalculateDescendants() that rely on them to
  * walk the mempool are not generally safe to use).
  *
  * Computational limits:
  *
  * Updating all in-mempool ancestors of a newly added transaction can be slow,
  * if no bound exists on how many in-mempool ancestors there may be.
  * CalculateMemPoolAncestors() takes configurable limits that are designed to
  * prevent these calculations from being too CPU intensive.
  */
 class CTxMemPool {
 private:
     //! Value n means that n times in 2^32 we check.
     uint32_t nCheckFrequency GUARDED_BY(cs);
     //! Used by getblocktemplate to trigger CreateNewBlock() invocation
     std::atomic<uint32_t> nTransactionsUpdated;
 
     //! sum of all mempool tx's sizes.
     uint64_t totalTxSize;
     //! sum of dynamic memory usage of all the map elements (NOT the maps
     //! themselves)
     uint64_t cachedInnerUsage;
 
     mutable int64_t lastRollingFeeUpdate;
     mutable bool blockSinceLastRollingFeeBump;
     //! minimum fee to get into the pool, decreases exponentially
     mutable double rollingMinimumFeeRate;
     mutable uint64_t m_epoch;
     mutable bool m_has_epoch_guard;
 
+    // In-memory counter for external mempool tracking purposes.
+    // This number is incremented once every time a transaction
+    // is added or removed from the mempool for any reason.
+    mutable uint64_t m_sequence_number{1};
+
     void trackPackageRemoved(const CFeeRate &rate) EXCLUSIVE_LOCKS_REQUIRED(cs);
 
     bool m_is_loaded GUARDED_BY(cs){false};
 
 public:
     // public only for testing
     static const int ROLLING_FEE_HALFLIFE = 60 * 60 * 12;
 
     typedef boost::multi_index_container<
         CTxMemPoolEntry, boost::multi_index::indexed_by<
                              // sorted by txid
                              boost::multi_index::hashed_unique<
                                  mempoolentry_txid, SaltedTxIdHasher>,
                              // sorted by fee rate
                              boost::multi_index::ordered_non_unique<
                                  boost::multi_index::tag<descendant_score>,
                                  boost::multi_index::identity<CTxMemPoolEntry>,
                                  CompareTxMemPoolEntryByDescendantScore>,
                              // sorted by entry time
                              boost::multi_index::ordered_non_unique<
                                  boost::multi_index::tag<entry_time>,
                                  boost::multi_index::identity<CTxMemPoolEntry>,
                                  CompareTxMemPoolEntryByEntryTime>,
                              // sorted by fee rate with ancestors
                              boost::multi_index::ordered_non_unique<
                                  boost::multi_index::tag<ancestor_score>,
                                  boost::multi_index::identity<CTxMemPoolEntry>,
                                  CompareTxMemPoolEntryByAncestorFee>>>
         indexed_transaction_set;
 
     /**
      * This mutex needs to be locked when accessing `mapTx` or other members
      * that are guarded by it.
      *
      * @par Consistency guarantees
      *
      * By design, it is guaranteed that:
      *
      * 1. Locking both `cs_main` and `mempool.cs` will give a view of mempool
      *    that is consistent with current chain tip (`::ChainActive()` and
      *    `CoinsTip()`) and is fully populated. Fully populated means that if
      * the current active chain is missing transactions that were present in a
      *    previously active chain, all the missing transactions will have been
      *    re-added to the mempool and should be present if they meet size and
      *    consistency constraints.
      *
      * 2. Locking `mempool.cs` without `cs_main` will give a view of a mempool
      *    consistent with some chain that was active since `cs_main` was last
      *    locked, and that is fully populated as described above. It is ok for
      *    code that only needs to query or remove transactions from the mempool
      *    to lock just `mempool.cs` without `cs_main`.
      *
      * To provide these guarantees, it is necessary to lock both `cs_main` and
      * `mempool.cs` whenever adding transactions to the mempool and whenever
      * changing the chain tip. It's necessary to keep both mutexes locked until
      * the mempool is consistent with the new chain tip and fully populated.
      */
     mutable RecursiveMutex cs;
     indexed_transaction_set mapTx GUARDED_BY(cs);
 
     using txiter = indexed_transaction_set::nth_index<0>::type::const_iterator;
     //! All tx hashes/entries in mapTx, in random order
     std::vector<std::pair<TxHash, txiter>> vTxHashes GUARDED_BY(cs);
 
     typedef std::set<txiter, CompareIteratorById> setEntries;
 
     uint64_t CalculateDescendantMaximum(txiter entry) const
         EXCLUSIVE_LOCKS_REQUIRED(cs);
 
 private:
     typedef std::map<txiter, setEntries, CompareIteratorById> cacheMap;
 
     void UpdateParent(txiter entry, txiter parent, bool add)
         EXCLUSIVE_LOCKS_REQUIRED(cs);
     void UpdateChild(txiter entry, txiter child, bool add)
         EXCLUSIVE_LOCKS_REQUIRED(cs);
 
     std::vector<indexed_transaction_set::const_iterator>
     GetSortedDepthAndScore() const EXCLUSIVE_LOCKS_REQUIRED(cs);
 
     /**
      * Track locally submitted transactions to periodically retry initial
      * broadcast
      */
     std::set<TxId> m_unbroadcast_txids GUARDED_BY(cs);
 
 public:
     indirectmap<COutPoint, const CTransaction *> mapNextTx GUARDED_BY(cs);
     std::map<TxId, Amount> mapDeltas;
 
     /**
      * Create a new CTxMemPool.
      */
     CTxMemPool();
     ~CTxMemPool();
 
     /**
      * If sanity-checking is turned on, check makes sure the pool is consistent
      * (does not contain two transactions that spend the same inputs, all inputs
      * are in the mapNextTx array). If sanity-checking is turned off, check does
      * nothing.
      */
     void check(const CCoinsViewCache *pcoins) const;
     void setSanityCheck(double dFrequency = 1.0) {
         LOCK(cs);
         nCheckFrequency = static_cast<uint32_t>(dFrequency * 4294967295.0);
     }
 
     // addUnchecked must updated state for all ancestors of a given transaction,
     // to track size/count of descendant transactions. First version of
     // addUnchecked can be used to have it call CalculateMemPoolAncestors(), and
     // then invoke the second version.
     // Note that addUnchecked is ONLY called from ATMP outside of tests
     // and any other callers may break wallet's in-mempool tracking (due to
     // lack of CValidationInterface::TransactionAddedToMempool callbacks).
     void addUnchecked(const CTxMemPoolEntry &entry)
         EXCLUSIVE_LOCKS_REQUIRED(cs, cs_main);
     void addUnchecked(const CTxMemPoolEntry &entry, setEntries &setAncestors)
         EXCLUSIVE_LOCKS_REQUIRED(cs, cs_main);
 
     void removeRecursive(const CTransaction &tx, MemPoolRemovalReason reason)
         EXCLUSIVE_LOCKS_REQUIRED(cs);
     void removeForReorg(const Config &config, const CCoinsViewCache *pcoins,
                         unsigned int nMemPoolHeight, int flags)
         EXCLUSIVE_LOCKS_REQUIRED(cs, cs_main);
     void removeConflicts(const CTransaction &tx) EXCLUSIVE_LOCKS_REQUIRED(cs);
     void removeForBlock(const std::vector<CTransactionRef> &vtx,
                         unsigned int nBlockHeight) EXCLUSIVE_LOCKS_REQUIRED(cs);
 
     void clear();
     // lock free
     void _clear() EXCLUSIVE_LOCKS_REQUIRED(cs);
     bool CompareDepthAndScore(const TxId &txida, const TxId &txidb);
     void queryHashes(std::vector<uint256> &vtxid) const;
     bool isSpent(const COutPoint &outpoint) const;
     unsigned int GetTransactionsUpdated() const;
     void AddTransactionsUpdated(unsigned int n);
     /**
      * Check that none of this transactions inputs are in the mempool, and thus
      * the tx is not dependent on other mempool transactions to be included in a
      * block.
      */
     bool HasNoInputsOf(const CTransaction &tx) const
         EXCLUSIVE_LOCKS_REQUIRED(cs);
 
     /** Affect CreateNewBlock prioritisation of transactions */
     void PrioritiseTransaction(const TxId &txid, const Amount nFeeDelta);
     void ApplyDelta(const TxId &txid, Amount &nFeeDelta) const
         EXCLUSIVE_LOCKS_REQUIRED(cs);
     void ClearPrioritisation(const TxId &txid) EXCLUSIVE_LOCKS_REQUIRED(cs);
 
     /** Get the transaction in the pool that spends the same prevout */
     const CTransaction *GetConflictTx(const COutPoint &prevout) const
         EXCLUSIVE_LOCKS_REQUIRED(cs);
 
     /** Returns an iterator to the given txid, if found */
     std::optional<txiter> GetIter(const TxId &txid) const
         EXCLUSIVE_LOCKS_REQUIRED(cs);
 
     /**
      * Translate a set of txids into a set of pool iterators to avoid repeated
      * lookups.
      */
     setEntries GetIterSet(const std::set<TxId> &txids) const
         EXCLUSIVE_LOCKS_REQUIRED(cs);
 
     /**
      * Remove a set of transactions from the mempool. If a transaction is in
      * this set, then all in-mempool descendants must also be in the set, unless
      * this transaction is being removed for being in a block. Set
      * updateDescendants to true when removing a tx that was in a block, so that
      * any in-mempool descendants have their ancestor state updated.
      */
     void RemoveStaged(setEntries &stage, bool updateDescendants,
                       MemPoolRemovalReason reason) EXCLUSIVE_LOCKS_REQUIRED(cs);
 
     /**
      * When adding transactions from a disconnected block back to the mempool,
      * new mempool entries may have children in the mempool (which is generally
      * not the case when otherwise adding transactions).
      * UpdateTransactionsFromBlock() will find child transactions and update the
      * descendant state for each transaction in txidsToUpdate (excluding any
      * child transactions present in txidsToUpdate, which are already accounted
      * for).
      * Note: txidsToUpdate should be the set of transactions from the
      * disconnected block that have been accepted back into the mempool.
      */
     void UpdateTransactionsFromBlock(const std::vector<TxId> &txidsToUpdate)
         EXCLUSIVE_LOCKS_REQUIRED(cs, cs_main);
 
     /**
      * Try to calculate all in-mempool ancestors of entry.
      *  (these are all calculated including the tx itself)
      *  limitAncestorCount = max number of ancestors
      *  limitAncestorSize = max size of ancestors
      *  limitDescendantCount = max number of descendants any ancestor can have
      *  limitDescendantSize = max size of descendants any ancestor can have
      *  errString = populated with error reason if any limits are hit
      * fSearchForParents = whether to search a tx's vin for in-mempool parents,
      * or look up parents from mapLinks. Must be true for entries not in the
      * mempool
      */
     bool CalculateMemPoolAncestors(
         const CTxMemPoolEntry &entry, setEntries &setAncestors,
         uint64_t limitAncestorCount, uint64_t limitAncestorSize,
         uint64_t limitDescendantCount, uint64_t limitDescendantSize,
         std::string &errString, bool fSearchForParents = true) const
         EXCLUSIVE_LOCKS_REQUIRED(cs);
 
     /**
      * Populate setDescendants with all in-mempool descendants of hash.
      * Assumes that setDescendants includes all in-mempool descendants of
      * anything already in it.
      */
     void CalculateDescendants(txiter it, setEntries &setDescendants) const
         EXCLUSIVE_LOCKS_REQUIRED(cs);
 
     /**
      * The minimum fee to get into the mempool, which may itself not be enough
      * for larger-sized transactions. The incrementalRelayFee policy variable is
      * used to bound the time it takes the fee rate to go back down all the way
      * to 0. When the feerate would otherwise be half of this, it is set to 0
      * instead.
      */
     CFeeRate GetMinFee(size_t sizelimit) const;
 
     /**
      * Remove transactions from the mempool until its dynamic size is <=
      * sizelimit. pvNoSpendsRemaining, if set, will be populated with the list
      * of outpoints which are not in mempool which no longer have any spends in
      * this mempool.
      */
     void TrimToSize(size_t sizelimit,
                     std::vector<COutPoint> *pvNoSpendsRemaining = nullptr)
         EXCLUSIVE_LOCKS_REQUIRED(cs);
 
     /**
      * Expire all transaction (and their dependencies) in the mempool older than
      * time. Return the number of removed transactions.
      */
     int Expire(std::chrono::seconds time) EXCLUSIVE_LOCKS_REQUIRED(cs);
 
     /**
      * Reduce the size of the mempool by expiring and then trimming the mempool.
      */
     void LimitSize(size_t limit, std::chrono::seconds age)
         EXCLUSIVE_LOCKS_REQUIRED(cs, ::cs_main);
 
     /**
      * Calculate the ancestor and descendant count for the given transaction.
      * The counts include the transaction itself.
      */
     void GetTransactionAncestry(const TxId &txid, size_t &ancestors,
                                 size_t &descendants) const;
 
     /** @returns true if the mempool is fully loaded */
     bool IsLoaded() const;
 
     /** Sets the current loaded state */
     void SetIsLoaded(bool loaded);
 
     unsigned long size() const {
         LOCK(cs);
         return mapTx.size();
     }
 
     uint64_t GetTotalTxSize() const EXCLUSIVE_LOCKS_REQUIRED(cs) {
         AssertLockHeld(cs);
         return totalTxSize;
     }
 
     bool exists(const TxId &txid) const {
         LOCK(cs);
         return mapTx.count(txid) != 0;
     }
 
     CTransactionRef get(const TxId &txid) const;
     TxMempoolInfo info(const TxId &txid) const;
     std::vector<TxMempoolInfo> infoAll() const;
 
     CFeeRate estimateFee() const;
 
     size_t DynamicMemoryUsage() const;
 
     /** Adds a transaction to the unbroadcast set */
     void AddUnbroadcastTx(const TxId &txid) {
         LOCK(cs);
         // Sanity Check: the transaction should also be in the mempool
         if (exists(txid)) {
             m_unbroadcast_txids.insert(txid);
         }
     }
 
     /** Removes a transaction from the unbroadcast set */
     void RemoveUnbroadcastTx(const TxId &txid, const bool unchecked = false);
 
     /** Returns transactions in unbroadcast set */
     std::set<TxId> GetUnbroadcastTxs() const {
         LOCK(cs);
         return m_unbroadcast_txids;
     }
 
     /** Returns whether a txid is in the unbroadcast set */
     bool IsUnbroadcastTx(const TxId &txid) const EXCLUSIVE_LOCKS_REQUIRED(cs) {
         AssertLockHeld(cs);
         return (m_unbroadcast_txids.count(txid) != 0);
     }
 
+    /** Guards this internal counter for external reporting */
+    uint64_t GetAndIncrementSequence() const EXCLUSIVE_LOCKS_REQUIRED(cs) {
+        return m_sequence_number++;
+    }
+
+    uint64_t GetSequence() const EXCLUSIVE_LOCKS_REQUIRED(cs) {
+        return m_sequence_number;
+    }
+
 private:
     /**
      * UpdateForDescendants is used by UpdateTransactionsFromBlock to update the
      * descendants for a single transaction that has been added to the mempool
      * but may have child transactions in the mempool, eg during a chain reorg.
      * setExclude is the set of descendant transactions in the mempool that must
      * not be accounted for (because any descendants in setExclude were added to
      * the mempool after the transaction being updated and hence their state is
      * already reflected in the parent state).
      *
      * cachedDescendants will be updated with the descendants of the transaction
      * being updated, so that future invocations don't need to walk the same
      * transaction again, if encountered in another transaction chain.
      */
     void UpdateForDescendants(txiter updateIt, cacheMap &cachedDescendants,
                               const std::set<TxId> &setExclude)
         EXCLUSIVE_LOCKS_REQUIRED(cs);
     /**
      * Update ancestors of hash to add/remove it as a descendant transaction.
      */
     void UpdateAncestorsOf(bool add, txiter hash, setEntries &setAncestors)
         EXCLUSIVE_LOCKS_REQUIRED(cs);
     /** Set ancestor state for an entry */
     void UpdateEntryForAncestors(txiter it, const setEntries &setAncestors)
         EXCLUSIVE_LOCKS_REQUIRED(cs);
     /**
      * For each transaction being removed, update ancestors and any direct
      * children. If updateDescendants is true, then also update in-mempool
      * descendants' ancestor state.
      */
     void UpdateForRemoveFromMempool(const setEntries &entriesToRemove,
                                     bool updateDescendants)
         EXCLUSIVE_LOCKS_REQUIRED(cs);
     /** Sever link between specified transaction and direct children. */
     void UpdateChildrenForRemoval(txiter entry) EXCLUSIVE_LOCKS_REQUIRED(cs);
 
     /**
      * Before calling removeUnchecked for a given transaction,
      * UpdateForRemoveFromMempool must be called on the entire (dependent) set
      * of transactions being removed at the same time. We use each
      * CTxMemPoolEntry's setMemPoolParents in order to walk ancestors of a given
      * transaction that is removed, so we can't remove intermediate transactions
      * in a chain before we've updated all the state for the removal.
      */
     void removeUnchecked(txiter entry, MemPoolRemovalReason reason)
         EXCLUSIVE_LOCKS_REQUIRED(cs);
 
 public:
     /**
      * EpochGuard: RAII-style guard for using epoch-based graph traversal
      * algorithms. When walking ancestors or descendants, we generally want to
      * avoid visiting the same transactions twice. Some traversal algorithms use
      * std::set (or setEntries) to deduplicate the transaction we visit.
      * However, use of std::set is algorithmically undesirable because it both
      * adds an asymptotic factor of O(log n) to traverals cost and triggers O(n)
      * more dynamic memory allocations.
      *     In many algorithms we can replace std::set with an internal mempool
      * counter to track the time (or, "epoch") that we began a traversal, and
      * check + update a per-transaction epoch for each transaction we look at to
      * determine if that transaction has not yet been visited during the current
      * traversal's epoch.
      *     Algorithms using std::set can be replaced on a one by one basis.
      * Both techniques are not fundamentally incompatible across the codebase.
      * Generally speaking, however, the remaining use of std::set for mempool
      * traversal should be viewed as a TODO for replacement with an epoch based
      * traversal, rather than a preference for std::set over epochs in that
      * algorithm.
      */
     class EpochGuard {
         const CTxMemPool &pool;
 
     public:
         EpochGuard(const CTxMemPool &in);
         ~EpochGuard();
     };
     // N.B. GetFreshEpoch modifies mutable state via the EpochGuard construction
     // (and later destruction)
     EpochGuard GetFreshEpoch() const EXCLUSIVE_LOCKS_REQUIRED(cs);
 
     /**
      * visited marks a CTxMemPoolEntry as having been traversed
      * during the lifetime of the most recently created EpochGuard
      * and returns false if we are the first visitor, true otherwise.
      *
      * An EpochGuard must be held when visited is called or an assert will be
      * triggered.
      *
      */
     bool visited(txiter it) const EXCLUSIVE_LOCKS_REQUIRED(cs) {
         assert(m_has_epoch_guard);
         bool ret = it->m_epoch >= m_epoch;
         it->m_epoch = std::max(it->m_epoch, m_epoch);
         return ret;
     }
 
     bool visited(std::optional<txiter> it) const EXCLUSIVE_LOCKS_REQUIRED(cs) {
         assert(m_has_epoch_guard);
         return !it || visited(*it);
     }
 };
 
 /**
  * CCoinsView that brings transactions from a mempool into view.
  * It does not check for spendings by memory pool transactions.
  * Instead, it provides access to all Coins which are either unspent in the
  * base CCoinsView, or are outputs from any mempool transaction!
  * This allows transaction replacement to work as expected, as you want to
  * have all inputs "available" to check signatures, and any cycles in the
  * dependency graph are checked directly in AcceptToMemoryPool.
  * It also allows you to sign a double-spend directly in
  * signrawtransactionwithkey and signrawtransactionwithwallet,
  * as long as the conflicting transaction is not yet confirmed.
  */
 class CCoinsViewMemPool : public CCoinsViewBacked {
 protected:
     const CTxMemPool &mempool;
 
 public:
     CCoinsViewMemPool(CCoinsView *baseIn, const CTxMemPool &mempoolIn);
     bool GetCoin(const COutPoint &outpoint, Coin &coin) const override;
 };
 
 /**
  * DisconnectedBlockTransactions
  *
  * During the reorg, it's desirable to re-add previously confirmed transactions
  * to the mempool, so that anything not re-confirmed in the new chain is
  * available to be mined. However, it's more efficient to wait until the reorg
  * is complete and process all still-unconfirmed transactions at that time,
  * since we expect most confirmed transactions to (typically) still be
  * confirmed in the new chain, and re-accepting to the memory pool is expensive
  * (and therefore better to not do in the middle of reorg-processing).
  * Instead, store the disconnected transactions (in order!) as we go, remove any
  * that are included in blocks in the new chain, and then process the remaining
  * still-unconfirmed transactions at the end.
  *
  * It also enables efficient reprocessing of current mempool entries, useful
  * when (de)activating forks that result in in-mempool transactions becoming
  * invalid
  */
 // multi_index tag names
 struct txid_index {};
 struct insertion_order {};
 
 class DisconnectedBlockTransactions {
 private:
     typedef boost::multi_index_container<
         CTransactionRef, boost::multi_index::indexed_by<
                              // sorted by txid
                              boost::multi_index::hashed_unique<
                                  boost::multi_index::tag<txid_index>,
                                  mempoolentry_txid, SaltedTxIdHasher>,
                              // sorted by order in the blockchain
                              boost::multi_index::sequenced<
                                  boost::multi_index::tag<insertion_order>>>>
         indexed_disconnected_transactions;
 
     indexed_disconnected_transactions queuedTx;
     uint64_t cachedInnerUsage = 0;
 
     void addTransaction(const CTransactionRef &tx) {
         queuedTx.insert(tx);
         cachedInnerUsage += RecursiveDynamicUsage(tx);
     }
 
 public:
     // It's almost certainly a logic bug if we don't clear out queuedTx before
     // destruction, as we add to it while disconnecting blocks, and then we
     // need to re-process remaining transactions to ensure mempool consistency.
     // For now, assert() that we've emptied out this object on destruction.
     // This assert() can always be removed if the reorg-processing code were
     // to be refactored such that this assumption is no longer true (for
     // instance if there was some other way we cleaned up the mempool after a
     // reorg, besides draining this object).
     ~DisconnectedBlockTransactions() { assert(queuedTx.empty()); }
 
     // Estimate the overhead of queuedTx to be 6 pointers + an allocation, as
     // no exact formula for boost::multi_index_contained is implemented.
     size_t DynamicMemoryUsage() const {
         return memusage::MallocUsage(sizeof(CTransactionRef) +
                                      6 * sizeof(void *)) *
                    queuedTx.size() +
                cachedInnerUsage;
     }
 
     const indexed_disconnected_transactions &GetQueuedTx() const {
         return queuedTx;
     }
 
     // Import mempool entries in topological order into queuedTx and clear the
     // mempool. Caller should call updateMempoolForReorg to reprocess these
     // transactions
     void importMempool(CTxMemPool &pool) EXCLUSIVE_LOCKS_REQUIRED(pool.cs);
 
     // Add entries for a block while reconstructing the topological ordering so
     // they can be added back to the mempool simply.
     void addForBlock(const std::vector<CTransactionRef> &vtx, CTxMemPool &pool)
         EXCLUSIVE_LOCKS_REQUIRED(pool.cs);
 
     // Remove entries based on txid_index, and update memory usage.
     void removeForBlock(const std::vector<CTransactionRef> &vtx) {
         // Short-circuit in the common case of a block being added to the tip
         if (queuedTx.empty()) {
             return;
         }
         for (auto const &tx : vtx) {
             auto it = queuedTx.find(tx->GetId());
             if (it != queuedTx.end()) {
                 cachedInnerUsage -= RecursiveDynamicUsage(*it);
                 queuedTx.erase(it);
             }
         }
     }
 
     // Remove an entry by insertion_order index, and update memory usage.
     void removeEntry(indexed_disconnected_transactions::index<
                      insertion_order>::type::iterator entry) {
         cachedInnerUsage -= RecursiveDynamicUsage(*entry);
         queuedTx.get<insertion_order>().erase(entry);
     }
 
     bool isEmpty() const { return queuedTx.empty(); }
 
     void clear() {
         cachedInnerUsage = 0;
         queuedTx.clear();
     }
 
     /**
      * Make mempool consistent after a reorg, by re-adding or recursively
      * erasing disconnected block transactions from the mempool, and also
      * removing any other transactions from the mempool that are no longer valid
      * given the new tip/height.
      *
      * Note: we assume that disconnectpool only contains transactions that are
      * NOT confirmed in the current chain nor already in the mempool (otherwise,
      * in-mempool descendants of such transactions would be removed).
      *
      * Passing fAddToMempool=false will skip trying to add the transactions
      * back, and instead just erase from the mempool as needed.
      */
     void updateMempoolForReorg(const Config &config, bool fAddToMempool,
                                CTxMemPool &pool)
         EXCLUSIVE_LOCKS_REQUIRED(cs_main, pool.cs);
 };
 
 #endif // BITCOIN_TXMEMPOOL_H
diff --git a/src/validation.cpp b/src/validation.cpp
index f520a7d0a..939deae6d 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -1,6126 +1,6128 @@
 // Copyright (c) 2009-2010 Satoshi Nakamoto
 // Copyright (c) 2009-2018 The Bitcoin Core developers
 // Copyright (c) 2017-2020 The Bitcoin developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <validation.h>
 
 #include <arith_uint256.h>
 #include <avalanche/avalanche.h>
 #include <avalanche/processor.h>
 #include <blockdb.h>
 #include <blockvalidity.h>
 #include <chainparams.h>
 #include <checkpoints.h>
 #include <checkqueue.h>
 #include <config.h>
 #include <consensus/activation.h>
 #include <consensus/merkle.h>
 #include <consensus/tx_check.h>
 #include <consensus/tx_verify.h>
 #include <consensus/validation.h>
 #include <hash.h>
 #include <index/txindex.h>
 #include <logging.h>
 #include <logging/timer.h>
 #include <minerfund.h>
 #include <node/ui_interface.h>
 #include <policy/fees.h>
 #include <policy/mempool.h>
 #include <policy/policy.h>
 #include <policy/settings.h>
 #include <pow/aserti32d.h> // For ResetASERTAnchorBlockCache
 #include <pow/pow.h>
 #include <primitives/block.h>
 #include <primitives/transaction.h>
 #include <random.h>
 #include <reverse_iterator.h>
 #include <script/script.h>
 #include <script/scriptcache.h>
 #include <script/sigcache.h>
 #include <shutdown.h>
 #include <timedata.h>
 #include <tinyformat.h>
 #include <txdb.h>
 #include <txmempool.h>
 #include <undo.h>
 #include <util/check.h> // For NDEBUG compile time check
 #include <util/moneystr.h>
 #include <util/strencodings.h>
 #include <util/system.h>
 #include <util/translation.h>
 #include <validationinterface.h>
 #include <warnings.h>
 
 #include <boost/algorithm/string/replace.hpp>
 
 #include <optional>
 #include <string>
 #include <thread>
 
 #define MICRO 0.000001
 #define MILLI 0.001
 
 /** Time to wait between writing blocks/block index to disk. */
 static constexpr std::chrono::hours DATABASE_WRITE_INTERVAL{1};
 /** Time to wait between flushing chainstate to disk. */
 static constexpr std::chrono::hours DATABASE_FLUSH_INTERVAL{24};
 const std::vector<std::string> CHECKLEVEL_DOC{
     "level 0 reads the blocks from disk",
     "level 1 verifies block validity",
     "level 2 verifies undo data",
     "level 3 checks disconnection of tip blocks",
     "level 4 tries to reconnect the blocks",
     "each level includes the checks of the previous levels",
 };
 
 ChainstateManager g_chainman;
 
 CChainState &ChainstateActive() {
     LOCK(::cs_main);
     assert(g_chainman.m_active_chainstate);
     return *g_chainman.m_active_chainstate;
 }
 
 CChain &ChainActive() {
     LOCK(::cs_main);
     return ::ChainstateActive().m_chain;
 }
 
 /**
  * Global state
  *
  * Mutex to guard access to validation specific variables, such as reading
  * or changing the chainstate.
  *
  * This may also need to be locked when updating the transaction pool, e.g. on
  * AcceptToMemoryPool. See CTxMemPool::cs comment for details.
  *
  * The transaction pool has a separate lock to allow reading from it and the
  * chainstate at the same time.
  */
 RecursiveMutex cs_main;
 
 CBlockIndex *pindexBestHeader = nullptr;
 Mutex g_best_block_mutex;
 std::condition_variable g_best_block_cv;
 uint256 g_best_block;
 std::atomic_bool fImporting(false);
 std::atomic_bool fReindex(false);
 bool fHavePruned = false;
 bool fPruneMode = false;
 bool fRequireStandard = true;
 bool fCheckBlockIndex = false;
 bool fCheckpointsEnabled = DEFAULT_CHECKPOINTS_ENABLED;
 uint64_t nPruneTarget = 0;
 int64_t nMaxTipAge = DEFAULT_MAX_TIP_AGE;
 
 BlockHash hashAssumeValid;
 arith_uint256 nMinimumChainWork;
 
 CFeeRate minRelayTxFee = CFeeRate(DEFAULT_MIN_RELAY_TX_FEE_PER_KB);
 
 // Internal stuff
 namespace {
 CBlockIndex *pindexBestInvalid = nullptr;
 CBlockIndex *pindexBestParked = nullptr;
 
 RecursiveMutex cs_LastBlockFile;
 std::vector<CBlockFileInfo> vinfoBlockFile;
 int nLastBlockFile = 0;
 /**
  * Global flag to indicate we should check to see if there are block/undo files
  * that should be deleted. Set on startup or if we allocate more file space when
  * we're in prune mode.
  */
 bool fCheckForPruning = false;
 
 /** Dirty block index entries. */
 std::set<const CBlockIndex *> setDirtyBlockIndex;
 
 /** Dirty block file entries. */
 std::set<int> setDirtyFileInfo;
 } // namespace
 
 BlockValidationOptions::BlockValidationOptions(const Config &config)
     : excessiveBlockSize(config.GetMaxBlockSize()), checkPoW(true),
       checkMerkleRoot(true) {}
 
 CBlockIndex *LookupBlockIndex(const BlockHash &hash) {
     AssertLockHeld(cs_main);
     BlockMap::const_iterator it = g_chainman.BlockIndex().find(hash);
     return it == g_chainman.BlockIndex().end() ? nullptr : it->second;
 }
 
 CBlockIndex *FindForkInGlobalIndex(const CChain &chain,
                                    const CBlockLocator &locator) {
     AssertLockHeld(cs_main);
 
     // Find the latest block common to locator and chain - we expect that
     // locator.vHave is sorted descending by height.
     for (const BlockHash &hash : locator.vHave) {
         CBlockIndex *pindex = LookupBlockIndex(hash);
         if (pindex) {
             if (chain.Contains(pindex)) {
                 return pindex;
             }
             if (pindex->GetAncestor(chain.Height()) == chain.Tip()) {
                 return chain.Tip();
             }
         }
     }
     return chain.Genesis();
 }
 
 std::unique_ptr<CBlockTreeDB> pblocktree;
 
 static uint32_t GetNextBlockScriptFlags(const Consensus::Params &params,
                                         const CBlockIndex *pindex);
 
 bool TestLockPointValidity(const LockPoints *lp) {
     AssertLockHeld(cs_main);
     assert(lp);
     // If there are relative lock times then the maxInputBlock will be set
     // If there are no relative lock times, the LockPoints don't depend on the
     // chain
     if (lp->maxInputBlock) {
         // Check whether ::ChainActive() is an extension of the block at which
         // the LockPoints calculation was valid. If not LockPoints are no longer
         // valid.
         if (!::ChainActive().Contains(lp->maxInputBlock)) {
             return false;
         }
     }
 
     // LockPoints still valid
     return true;
 }
 
 bool CheckSequenceLocks(const CTxMemPool &pool, const CTransaction &tx,
                         int flags, LockPoints *lp, bool useExistingLockPoints) {
     AssertLockHeld(cs_main);
     AssertLockHeld(pool.cs);
 
     CBlockIndex *tip = ::ChainActive().Tip();
     assert(tip != nullptr);
 
     CBlockIndex index;
     index.pprev = tip;
     // CheckSequenceLocks() uses ::ChainActive().Height()+1 to evaluate height
     // based locks because when SequenceLocks() is called within ConnectBlock(),
     // the height of the block *being* evaluated is what is used. Thus if we
     // want to know if a transaction can be part of the *next* block, we need to
     // use one more than ::ChainActive().Height()
     index.nHeight = tip->nHeight + 1;
 
     std::pair<int, int64_t> lockPair;
     if (useExistingLockPoints) {
         assert(lp);
         lockPair.first = lp->height;
         lockPair.second = lp->time;
     } else {
         // CoinsTip() contains the UTXO set for ::ChainActive().Tip()
         CCoinsViewMemPool viewMemPool(&::ChainstateActive().CoinsTip(), pool);
         std::vector<int> prevheights;
         prevheights.resize(tx.vin.size());
         for (size_t txinIndex = 0; txinIndex < tx.vin.size(); txinIndex++) {
             const CTxIn &txin = tx.vin[txinIndex];
             Coin coin;
             if (!viewMemPool.GetCoin(txin.prevout, coin)) {
                 return error("%s: Missing input", __func__);
             }
             if (coin.GetHeight() == MEMPOOL_HEIGHT) {
                 // Assume all mempool transaction confirm in the next block
                 prevheights[txinIndex] = tip->nHeight + 1;
             } else {
                 prevheights[txinIndex] = coin.GetHeight();
             }
         }
         lockPair = CalculateSequenceLocks(tx, flags, prevheights, index);
         if (lp) {
             lp->height = lockPair.first;
             lp->time = lockPair.second;
             // Also store the hash of the block with the highest height of all
             // the blocks which have sequence locked prevouts. This hash needs
             // to still be on the chain for these LockPoint calculations to be
             // valid.
             // Note: It is impossible to correctly calculate a maxInputBlock if
             // any of the sequence locked inputs depend on unconfirmed txs,
             // except in the special case where the relative lock time/height is
             // 0, which is equivalent to no sequence lock. Since we assume input
             // height of tip+1 for mempool txs and test the resulting lockPair
             // from CalculateSequenceLocks against tip+1. We know
             // EvaluateSequenceLocks will fail if there was a non-zero sequence
             // lock on a mempool input, so we can use the return value of
             // CheckSequenceLocks to indicate the LockPoints validity.
             int maxInputHeight = 0;
             for (const int height : prevheights) {
                 // Can ignore mempool inputs since we'll fail if they had
                 // non-zero locks.
                 if (height != tip->nHeight + 1) {
                     maxInputHeight = std::max(maxInputHeight, height);
                 }
             }
             lp->maxInputBlock = tip->GetAncestor(maxInputHeight);
         }
     }
     return EvaluateSequenceLocks(index, lockPair);
 }
 
 // Command-line argument "-replayprotectionactivationtime=<timestamp>" will
 // cause the node to switch to replay protected SigHash ForkID value when the
 // median timestamp of the previous 11 blocks is greater than or equal to
 // <timestamp>. Defaults to the pre-defined timestamp when not set.
 static bool IsReplayProtectionEnabled(const Consensus::Params &params,
                                       int64_t nMedianTimePast) {
     return nMedianTimePast >= gArgs.GetArg("-replayprotectionactivationtime",
                                            params.gluonActivationTime);
 }
 
 static bool IsReplayProtectionEnabled(const Consensus::Params &params,
                                       const CBlockIndex *pindexPrev) {
     if (pindexPrev == nullptr) {
         return false;
     }
 
     return IsReplayProtectionEnabled(params, pindexPrev->GetMedianTimePast());
 }
 
 // Used to avoid mempool polluting consensus critical paths if CCoinsViewMempool
 // were somehow broken and returning the wrong scriptPubKeys
 static bool CheckInputsFromMempoolAndCache(
     const CTransaction &tx, TxValidationState &state,
     const CCoinsViewCache &view, const CTxMemPool &pool, const uint32_t flags,
     PrecomputedTransactionData &txdata, int &nSigChecksOut)
     EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
     AssertLockHeld(cs_main);
 
     // pool.cs should be locked already, but go ahead and re-take the lock here
     // to enforce that mempool doesn't change between when we check the view and
     // when we actually call through to CheckInputScripts
     LOCK(pool.cs);
 
     assert(!tx.IsCoinBase());
     for (const CTxIn &txin : tx.vin) {
         const Coin &coin = view.AccessCoin(txin.prevout);
 
         // AcceptToMemoryPoolWorker has already checked that the coins are
         // available, so this shouldn't fail. If the inputs are not available
         // here then return false.
         if (coin.IsSpent()) {
             return false;
         }
 
         // Check equivalence for available inputs.
         const CTransactionRef &txFrom = pool.get(txin.prevout.GetTxId());
         if (txFrom) {
             assert(txFrom->GetId() == txin.prevout.GetTxId());
             assert(txFrom->vout.size() > txin.prevout.GetN());
             assert(txFrom->vout[txin.prevout.GetN()] == coin.GetTxOut());
         } else {
             const Coin &coinFromDisk =
                 ::ChainstateActive().CoinsTip().AccessCoin(txin.prevout);
             assert(!coinFromDisk.IsSpent());
             assert(coinFromDisk.GetTxOut() == coin.GetTxOut());
         }
     }
 
     // Call CheckInputScripts() to cache signature and script validity against
     // current tip consensus rules.
     return CheckInputScripts(tx, state, view, flags, /* cacheSigStore = */ true,
                              /* cacheFullScriptStore = */ true, txdata,
                              nSigChecksOut);
 }
 
 namespace {
 
 class MemPoolAccept {
 public:
     MemPoolAccept(CTxMemPool &mempool)
         : m_pool(mempool), m_view(&m_dummy),
           m_viewmempool(&::ChainstateActive().CoinsTip(), m_pool),
           m_limit_ancestors(
               gArgs.GetArg("-limitancestorcount", DEFAULT_ANCESTOR_LIMIT)),
           m_limit_ancestor_size(
               gArgs.GetArg("-limitancestorsize", DEFAULT_ANCESTOR_SIZE_LIMIT) *
               1000),
           m_limit_descendants(
               gArgs.GetArg("-limitdescendantcount", DEFAULT_DESCENDANT_LIMIT)),
           m_limit_descendant_size(gArgs.GetArg("-limitdescendantsize",
                                                DEFAULT_DESCENDANT_SIZE_LIMIT) *
                                   1000) {}
 
     // We put the arguments we're handed into a struct, so we can pass them
     // around easier.
     struct ATMPArgs {
         const Config &m_config;
         TxValidationState &m_state;
         const int64_t m_accept_time;
         const bool m_bypass_limits;
         const Amount &m_absurd_fee;
         /*
          * Return any outpoints which were not previously present in the coins
          * cache, but were added as a result of validating the tx for mempool
          * acceptance. This allows the caller to optionally remove the cache
          * additions if the associated transaction ends up being rejected by
          * the mempool.
          */
         std::vector<COutPoint> &m_coins_to_uncache;
         const bool m_test_accept;
         Amount *m_fee_out;
     };
 
     // Single transaction acceptance
     bool AcceptSingleTransaction(const CTransactionRef &ptx, ATMPArgs &args)
         EXCLUSIVE_LOCKS_REQUIRED(cs_main);
 
 private:
     // All the intermediate state that gets passed between the various levels
     // of checking a given transaction.
     struct Workspace {
         Workspace(const CTransactionRef &ptx,
                   const uint32_t next_block_script_verify_flags)
             : m_ptx(ptx),
               m_next_block_script_verify_flags(next_block_script_verify_flags) {
         }
         CTxMemPool::setEntries m_ancestors;
         std::unique_ptr<CTxMemPoolEntry> m_entry;
 
         Amount m_modified_fees;
 
         const CTransactionRef &m_ptx;
 
         // ABC specific flags that are used in both PreChecks and
         // ConsensusScriptChecks
         const uint32_t m_next_block_script_verify_flags;
         int m_sig_checks_standard;
     };
 
     // Run the policy checks on a given transaction, excluding any script
     // checks. Looks up inputs, calculates feerate, considers replacement,
     // evaluates package limits, etc. As this function can be invoked for "free"
     // by a peer, only tests that are fast should be done here (to avoid CPU
     // DoS).
     bool PreChecks(ATMPArgs &args, Workspace &ws)
         EXCLUSIVE_LOCKS_REQUIRED(cs_main, m_pool.cs);
 
     // Re-run the script checks, using consensus flags, and try to cache the
     // result in the scriptcache. This should be done after
     // PolicyScriptChecks(). This requires that all inputs either be in our
     // utxo set or in the mempool.
     bool ConsensusScriptChecks(ATMPArgs &args, Workspace &ws,
                                PrecomputedTransactionData &txdata)
         EXCLUSIVE_LOCKS_REQUIRED(cs_main);
 
     // Try to add the transaction to the mempool, removing any conflicts first.
     // Returns true if the transaction is in the mempool after any size
     // limiting is performed, false otherwise.
     bool Finalize(ATMPArgs &args, Workspace &ws)
         EXCLUSIVE_LOCKS_REQUIRED(cs_main, m_pool.cs);
 
 private:
     CTxMemPool &m_pool;
     CCoinsViewCache m_view;
     CCoinsViewMemPool m_viewmempool;
     CCoinsView m_dummy;
 
     // The package limits in effect at the time of invocation.
     const size_t m_limit_ancestors;
     const size_t m_limit_ancestor_size;
     // These may be modified while evaluating a transaction (eg to account for
     // in-mempool conflicts; see below).
     size_t m_limit_descendants;
     size_t m_limit_descendant_size;
 };
 
 bool MemPoolAccept::PreChecks(ATMPArgs &args, Workspace &ws) {
     const CTransactionRef &ptx = ws.m_ptx;
     const CTransaction &tx = *ws.m_ptx;
     const TxId &txid = ws.m_ptx->GetId();
 
     // Copy/alias what we need out of args
     TxValidationState &state = args.m_state;
     const int64_t nAcceptTime = args.m_accept_time;
     const bool bypass_limits = args.m_bypass_limits;
     const Amount &nAbsurdFee = args.m_absurd_fee;
     std::vector<COutPoint> &coins_to_uncache = args.m_coins_to_uncache;
 
     // Alias what we need out of ws
     CTxMemPool::setEntries &setAncestors = ws.m_ancestors;
     std::unique_ptr<CTxMemPoolEntry> &entry = ws.m_entry;
     Amount &nModifiedFees = ws.m_modified_fees;
 
     // Coinbase is only valid in a block, not as a loose transaction.
     if (!CheckRegularTransaction(tx, state)) {
         // state filled in by CheckRegularTransaction.
         return false;
     }
 
     // Rather not work on nonstandard transactions (unless -testnet)
     std::string reason;
     if (fRequireStandard && !IsStandardTx(tx, reason)) {
         return state.Invalid(TxValidationResult::TX_NOT_STANDARD, reason);
     }
 
     // Only accept nLockTime-using transactions that can be mined in the next
     // block; we don't want our mempool filled up with transactions that can't
     // be mined yet.
     TxValidationState ctxState;
     if (!ContextualCheckTransactionForCurrentBlock(
             args.m_config.GetChainParams().GetConsensus(), tx, ctxState,
             STANDARD_LOCKTIME_VERIFY_FLAGS)) {
         // We copy the state from a dummy to ensure we don't increase the
         // ban score of peer for transaction that could be valid in the future.
         return state.Invalid(TxValidationResult::TX_PREMATURE_SPEND,
                              ctxState.GetRejectReason(),
                              ctxState.GetDebugMessage());
     }
 
     // Is it already in the memory pool?
     if (m_pool.exists(txid)) {
         return state.Invalid(TxValidationResult::TX_CONFLICT,
                              "txn-already-in-mempool");
     }
 
     // Check for conflicts with in-memory transactions
     for (const CTxIn &txin : tx.vin) {
         auto itConflicting = m_pool.mapNextTx.find(txin.prevout);
         if (itConflicting != m_pool.mapNextTx.end()) {
             // Disable replacement feature for good
             return state.Invalid(TxValidationResult::TX_MEMPOOL_POLICY,
                                  "txn-mempool-conflict");
         }
     }
 
     LockPoints lp;
     m_view.SetBackend(m_viewmempool);
 
     CCoinsViewCache &coins_cache = ::ChainstateActive().CoinsTip();
     // Do all inputs exist?
     for (const CTxIn &txin : tx.vin) {
         if (!coins_cache.HaveCoinInCache(txin.prevout)) {
             coins_to_uncache.push_back(txin.prevout);
         }
 
         // Note: this call may add txin.prevout to the coins cache
         // (coins_cache.cacheCoins) by way of FetchCoin(). It should be
         // removed later (via coins_to_uncache) if this tx turns out to be
         // invalid.
         if (!m_view.HaveCoin(txin.prevout)) {
             // Are inputs missing because we already have the tx?
             for (size_t out = 0; out < tx.vout.size(); out++) {
                 // Optimistically just do efficient check of cache for
                 // outputs.
                 if (coins_cache.HaveCoinInCache(COutPoint(txid, out))) {
                     return state.Invalid(TxValidationResult::TX_CONFLICT,
                                          "txn-already-known");
                 }
             }
 
             // Otherwise assume this might be an orphan tx for which we just
             // haven't seen parents yet.
             return state.Invalid(TxValidationResult::TX_MISSING_INPUTS,
                                  "bad-txns-inputs-missingorspent");
         }
     }
 
     // Are the actual inputs available?
     if (!m_view.HaveInputs(tx)) {
         return state.Invalid(TxValidationResult::TX_MEMPOOL_POLICY,
                              "bad-txns-inputs-spent");
     }
 
     // Bring the best block into scope.
     m_view.GetBestBlock();
 
     // we have all inputs cached now, so switch back to dummy (to protect
     // against bugs where we pull more inputs from disk that miss being
     // added to coins_to_uncache)
     m_view.SetBackend(m_dummy);
 
     // Only accept BIP68 sequence locked transactions that can be mined in
     // the next block; we don't want our mempool filled up with transactions
     // that can't be mined yet. Must keep pool.cs for this unless we change
     // CheckSequenceLocks to take a CoinsViewCache instead of create its
     // own.
     if (!CheckSequenceLocks(m_pool, tx, STANDARD_LOCKTIME_VERIFY_FLAGS, &lp)) {
         return state.Invalid(TxValidationResult::TX_PREMATURE_SPEND,
                              "non-BIP68-final");
     }
 
     Amount nFees = Amount::zero();
     if (!Consensus::CheckTxInputs(tx, state, m_view, GetSpendHeight(m_view),
                                   nFees)) {
         // state filled in by CheckTxInputs
         return false;
     }
 
     // If fee_out is passed, return the fee to the caller
     if (args.m_fee_out) {
         *args.m_fee_out = nFees;
     }
 
     // Check for non-standard pay-to-script-hash in inputs
     if (fRequireStandard &&
         !AreInputsStandard(tx, m_view, ws.m_next_block_script_verify_flags)) {
         return state.Invalid(TxValidationResult::TX_INPUTS_NOT_STANDARD,
                              "bad-txns-nonstandard-inputs");
     }
 
     // nModifiedFees includes any fee deltas from PrioritiseTransaction
     nModifiedFees = nFees;
     m_pool.ApplyDelta(txid, nModifiedFees);
 
     // Keep track of transactions that spend a coinbase, which we re-scan
     // during reorgs to ensure COINBASE_MATURITY is still met.
     bool fSpendsCoinbase = false;
     for (const CTxIn &txin : tx.vin) {
         const Coin &coin = m_view.AccessCoin(txin.prevout);
         if (coin.IsCoinBase()) {
             fSpendsCoinbase = true;
             break;
         }
     }
 
     unsigned int nSize = tx.GetTotalSize();
 
     // No transactions are allowed below minRelayTxFee except from disconnected
     // blocks.
     // Do not change this to use virtualsize without coordinating a network
     // policy upgrade.
     if (!bypass_limits && nModifiedFees < minRelayTxFee.GetFee(nSize)) {
         return state.Invalid(
             TxValidationResult::TX_MEMPOOL_POLICY, "min relay fee not met",
             strprintf("%d < %d", nModifiedFees, ::minRelayTxFee.GetFee(nSize)));
     }
 
     if (nAbsurdFee != Amount::zero() && nFees > nAbsurdFee) {
         return state.Invalid(TxValidationResult::TX_NOT_STANDARD,
                              "absurdly-high-fee",
                              strprintf("%d > %d", nFees, nAbsurdFee));
     }
 
     // Validate input scripts against standard script flags.
     const uint32_t scriptVerifyFlags =
         ws.m_next_block_script_verify_flags | STANDARD_SCRIPT_VERIFY_FLAGS;
     PrecomputedTransactionData txdata(tx);
     if (!CheckInputScripts(tx, state, m_view, scriptVerifyFlags, true, false,
                            txdata, ws.m_sig_checks_standard)) {
         // State filled in by CheckInputScripts
         return false;
     }
 
     entry.reset(new CTxMemPoolEntry(ptx, nFees, nAcceptTime,
                                     ::ChainActive().Height(), fSpendsCoinbase,
                                     ws.m_sig_checks_standard, lp));
 
     unsigned int nVirtualSize = entry->GetTxVirtualSize();
 
     Amount mempoolRejectFee =
         m_pool
             .GetMinFee(gArgs.GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) *
                        1000000)
             .GetFee(nVirtualSize);
     if (!bypass_limits && mempoolRejectFee > Amount::zero() &&
         nModifiedFees < mempoolRejectFee) {
         return state.Invalid(
             TxValidationResult::TX_MEMPOOL_POLICY, "mempool min fee not met",
             strprintf("%d < %d", nModifiedFees, mempoolRejectFee));
     }
 
     // Calculate in-mempool ancestors, up to a limit.
     std::string errString;
     if (!m_pool.CalculateMemPoolAncestors(
             *entry, setAncestors, m_limit_ancestors, m_limit_ancestor_size,
             m_limit_descendants, m_limit_descendant_size, errString)) {
         return state.Invalid(TxValidationResult::TX_MEMPOOL_POLICY,
                              "too-long-mempool-chain", errString);
     }
     return true;
 }
 
 bool MemPoolAccept::ConsensusScriptChecks(ATMPArgs &args, Workspace &ws,
                                           PrecomputedTransactionData &txdata) {
     const CTransaction &tx = *ws.m_ptx;
     const TxId &txid = tx.GetId();
 
     TxValidationState &state = args.m_state;
 
     // Check again against the next block's script verification flags
     // to cache our script execution flags.
     //
     // This is also useful in case of bugs in the standard flags that cause
     // transactions to pass as valid when they're actually invalid. For
     // instance the STRICTENC flag was incorrectly allowing certain CHECKSIG
     // NOT scripts to pass, even though they were invalid.
     //
     // There is a similar check in CreateNewBlock() to prevent creating
     // invalid blocks (using TestBlockValidity), however allowing such
     // transactions into the mempool can be exploited as a DoS attack.
     int nSigChecksConsensus;
     if (!CheckInputsFromMempoolAndCache(tx, state, m_view, m_pool,
                                         ws.m_next_block_script_verify_flags,
                                         txdata, nSigChecksConsensus)) {
         // This can occur under some circumstances, if the node receives an
         // unrequested tx which is invalid due to new consensus rules not
         // being activated yet (during IBD).
         return error("%s: BUG! PLEASE REPORT THIS! CheckInputScripts failed "
                      "against next-block but not STANDARD flags %s, %s",
                      __func__, txid.ToString(), state.ToString());
     }
 
     if (ws.m_sig_checks_standard != nSigChecksConsensus) {
         // We can't accept this transaction as we've used the standard count
         // for the mempool/mining, but the consensus count will be enforced
         // in validation (we don't want to produce bad block templates).
         return error(
             "%s: BUG! PLEASE REPORT THIS! SigChecks count differed between "
             "standard and consensus flags in %s",
             __func__, txid.ToString());
     }
     return true;
 }
 
 bool MemPoolAccept::Finalize(ATMPArgs &args, Workspace &ws) {
     const TxId &txid = ws.m_ptx->GetId();
     TxValidationState &state = args.m_state;
     const bool bypass_limits = args.m_bypass_limits;
 
     CTxMemPool::setEntries &setAncestors = ws.m_ancestors;
     std::unique_ptr<CTxMemPoolEntry> &entry = ws.m_entry;
 
     // Store transaction in memory.
     m_pool.addUnchecked(*entry, setAncestors);
 
     // Trim mempool and check if tx was trimmed.
     if (!bypass_limits) {
         m_pool.LimitSize(
             gArgs.GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000,
             std::chrono::hours{
                 gArgs.GetArg("-mempoolexpiry", DEFAULT_MEMPOOL_EXPIRY)});
         if (!m_pool.exists(txid)) {
             return state.Invalid(TxValidationResult::TX_MEMPOOL_POLICY,
                                  "mempool full");
         }
     }
     return true;
 }
 
 bool MemPoolAccept::AcceptSingleTransaction(const CTransactionRef &ptx,
                                             ATMPArgs &args) {
     AssertLockHeld(cs_main);
     // mempool "read lock" (held through
     // GetMainSignals().TransactionAddedToMempool())
     LOCK(m_pool.cs);
 
     Workspace workspace(ptx, GetNextBlockScriptFlags(
                                  args.m_config.GetChainParams().GetConsensus(),
                                  ::ChainActive().Tip()));
 
     if (!PreChecks(args, workspace)) {
         return false;
     }
 
     // Only compute the precomputed transaction data if we need to verify
     // scripts (ie, other policy checks pass). We perform the inexpensive
     // checks first and avoid hashing and signature verification unless those
     // checks pass, to mitigate CPU exhaustion denial-of-service attacks.
     PrecomputedTransactionData txdata(*ptx);
 
     if (!ConsensusScriptChecks(args, workspace, txdata)) {
         return false;
     }
 
     // Tx was accepted, but not added
     if (args.m_test_accept) {
         return true;
     }
 
     if (!Finalize(args, workspace)) {
         return false;
     }
 
-    GetMainSignals().TransactionAddedToMempool(ptx);
+    GetMainSignals().TransactionAddedToMempool(
+        ptx, m_pool.GetAndIncrementSequence());
+
     return true;
 }
 
 } // namespace
 
 /**
  * (try to) add transaction to memory pool with a specified acceptance time.
  */
 static bool AcceptToMemoryPoolWithTime(
     const Config &config, CTxMemPool &pool, TxValidationState &state,
     const CTransactionRef &tx, int64_t nAcceptTime, bool bypass_limits,
     const Amount nAbsurdFee, bool test_accept, Amount *fee_out = nullptr)
     EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
     AssertLockHeld(cs_main);
     std::vector<COutPoint> coins_to_uncache;
     MemPoolAccept::ATMPArgs args{config,        state,      nAcceptTime,
                                  bypass_limits, nAbsurdFee, coins_to_uncache,
                                  test_accept,   fee_out};
     bool res = MemPoolAccept(pool).AcceptSingleTransaction(tx, args);
     if (!res) {
         // Remove coins that were not present in the coins cache before calling
         // ATMPW; this is to prevent memory DoS in case we receive a large
         // number of invalid transactions that attempt to overrun the in-memory
         // coins cache
         // (`CCoinsViewCache::cacheCoins`).
 
         for (const COutPoint &outpoint : coins_to_uncache) {
             ::ChainstateActive().CoinsTip().Uncache(outpoint);
         }
     }
 
     // After we've (potentially) uncached entries, ensure our coins cache is
     // still within its size limits
     BlockValidationState stateDummy;
     ::ChainstateActive().FlushStateToDisk(config.GetChainParams(), stateDummy,
                                           FlushStateMode::PERIODIC);
     return res;
 }
 
 bool AcceptToMemoryPool(const Config &config, CTxMemPool &pool,
                         TxValidationState &state, const CTransactionRef &tx,
                         bool bypass_limits, const Amount nAbsurdFee,
                         bool test_accept, Amount *fee_out) {
     return AcceptToMemoryPoolWithTime(config, pool, state, tx, GetTime(),
                                       bypass_limits, nAbsurdFee, test_accept,
                                       fee_out);
 }
 
 CTransactionRef GetTransaction(const CBlockIndex *const block_index,
                                const CTxMemPool *const mempool,
                                const TxId &txid,
                                const Consensus::Params &consensusParams,
                                BlockHash &hashBlock) {
     LOCK(cs_main);
 
     if (block_index) {
         CBlock block;
         if (ReadBlockFromDisk(block, block_index, consensusParams)) {
             for (const auto &tx : block.vtx) {
                 if (tx->GetId() == txid) {
                     hashBlock = block_index->GetBlockHash();
                     return tx;
                 }
             }
         }
         return nullptr;
     }
     if (mempool) {
         CTransactionRef ptx = mempool->get(txid);
         if (ptx) {
             return ptx;
         }
     }
     if (g_txindex) {
         CTransactionRef tx;
         if (g_txindex->FindTx(txid, hashBlock, tx)) {
             return tx;
         }
     }
     return nullptr;
 }
 
 //////////////////////////////////////////////////////////////////////////////
 //
 // CBlock and CBlockIndex
 //
 
 static bool WriteBlockToDisk(const CBlock &block, FlatFilePos &pos,
                              const CMessageHeader::MessageMagic &messageStart) {
     // Open history file to append
     CAutoFile fileout(OpenBlockFile(pos), SER_DISK, CLIENT_VERSION);
     if (fileout.IsNull()) {
         return error("WriteBlockToDisk: OpenBlockFile failed");
     }
 
     // Write index header
     unsigned int nSize = GetSerializeSize(block, fileout.GetVersion());
     fileout << messageStart << nSize;
 
     // Write block
     long fileOutPos = ftell(fileout.Get());
     if (fileOutPos < 0) {
         return error("WriteBlockToDisk: ftell failed");
     }
 
     pos.nPos = (unsigned int)fileOutPos;
     fileout << block;
 
     return true;
 }
 
 Amount GetBlockSubsidy(int nHeight, const Consensus::Params &consensusParams) {
     int halvings = nHeight / consensusParams.nSubsidyHalvingInterval;
     // Force block reward to zero when right shift is undefined.
     if (halvings >= 64) {
         return Amount::zero();
     }
 
     Amount nSubsidy = 50 * COIN;
     // Subsidy is cut in half every 210,000 blocks which will occur
     // approximately every 4 years.
     return ((nSubsidy / SATOSHI) >> halvings) * SATOSHI;
 }
 
 CoinsViews::CoinsViews(std::string ldb_name, size_t cache_size_bytes,
                        bool in_memory, bool should_wipe)
     : m_dbview(GetDataDir() / ldb_name, cache_size_bytes, in_memory,
                should_wipe),
       m_catcherview(&m_dbview) {}
 
 void CoinsViews::InitCache() {
     m_cacheview = std::make_unique<CCoinsViewCache>(&m_catcherview);
 }
 
 CChainState::CChainState(CTxMemPool &mempool, BlockManager &blockman,
                          BlockHash from_snapshot_blockhash)
     : m_blockman(blockman), m_mempool(mempool),
       m_from_snapshot_blockhash(from_snapshot_blockhash) {}
 
 void CChainState::InitCoinsDB(size_t cache_size_bytes, bool in_memory,
                               bool should_wipe, std::string leveldb_name) {
     if (!m_from_snapshot_blockhash.IsNull()) {
         leveldb_name += "_" + m_from_snapshot_blockhash.ToString();
     }
     m_coins_views = std::make_unique<CoinsViews>(leveldb_name, cache_size_bytes,
                                                  in_memory, should_wipe);
 }
 
 void CChainState::InitCoinsCache(size_t cache_size_bytes) {
     assert(m_coins_views != nullptr);
     m_coinstip_cache_size_bytes = cache_size_bytes;
     m_coins_views->InitCache();
 }
 
 // Note that though this is marked const, we may end up modifying
 // `m_cached_finished_ibd`, which is a performance-related implementation
 // detail. This function must be marked `const` so that `CValidationInterface`
 // clients (which are given a `const CChainState*`) can call it.
 //
 bool CChainState::IsInitialBlockDownload() const {
     // Optimization: pre-test latch before taking the lock.
     if (m_cached_finished_ibd.load(std::memory_order_relaxed)) {
         return false;
     }
 
     LOCK(cs_main);
     if (m_cached_finished_ibd.load(std::memory_order_relaxed)) {
         return false;
     }
     if (fImporting || fReindex) {
         return true;
     }
     if (m_chain.Tip() == nullptr) {
         return true;
     }
     if (m_chain.Tip()->nChainWork < nMinimumChainWork) {
         return true;
     }
     if (m_chain.Tip()->GetBlockTime() < (GetTime() - nMaxTipAge)) {
         return true;
     }
     LogPrintf("Leaving InitialBlockDownload (latching to false)\n");
     m_cached_finished_ibd.store(true, std::memory_order_relaxed);
     return false;
 }
 
 static CBlockIndex const *pindexBestForkTip = nullptr;
 static CBlockIndex const *pindexBestForkBase = nullptr;
 
 static void AlertNotify(const std::string &strMessage) {
     uiInterface.NotifyAlertChanged();
 #if defined(HAVE_SYSTEM)
     std::string strCmd = gArgs.GetArg("-alertnotify", "");
     if (strCmd.empty()) {
         return;
     }
 
     // Alert text should be plain ascii coming from a trusted source, but to be
     // safe we first strip anything not in safeChars, then add single quotes
     // around the whole string before passing it to the shell:
     std::string singleQuote("'");
     std::string safeStatus = SanitizeString(strMessage);
     safeStatus = singleQuote + safeStatus + singleQuote;
     boost::replace_all(strCmd, "%s", safeStatus);
 
     std::thread t(runCommand, strCmd);
     // thread runs free
     t.detach();
 #endif
 }
 
 static void CheckForkWarningConditions() EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
     AssertLockHeld(cs_main);
     // Before we get past initial download, we cannot reliably alert about forks
     // (we assume we don't get stuck on a fork before finishing our initial
     // sync)
     if (::ChainstateActive().IsInitialBlockDownload()) {
         return;
     }
 
     // If our best fork is no longer within 72 blocks (+/- 12 hours if no one
     // mines it) of our head, drop it
     if (pindexBestForkTip &&
         ::ChainActive().Height() - pindexBestForkTip->nHeight >= 72) {
         pindexBestForkTip = nullptr;
     }
 
     if (pindexBestForkTip ||
         (pindexBestInvalid &&
          pindexBestInvalid->nChainWork >
              ::ChainActive().Tip()->nChainWork +
                  (GetBlockProof(*::ChainActive().Tip()) * 6))) {
         if (!GetfLargeWorkForkFound() && pindexBestForkBase) {
             std::string warning =
                 std::string("'Warning: Large-work fork detected, forking after "
                             "block ") +
                 pindexBestForkBase->phashBlock->ToString() + std::string("'");
             AlertNotify(warning);
         }
 
         if (pindexBestForkTip && pindexBestForkBase) {
             LogPrintf("%s: Warning: Large fork found\n  forking the "
                       "chain at height %d (%s)\n  lasting to height %d "
                       "(%s).\nChain state database corruption likely.\n",
                       __func__, pindexBestForkBase->nHeight,
                       pindexBestForkBase->phashBlock->ToString(),
                       pindexBestForkTip->nHeight,
                       pindexBestForkTip->phashBlock->ToString());
             SetfLargeWorkForkFound(true);
         } else {
             LogPrintf("%s: Warning: Found invalid chain at least ~6 blocks "
                       "longer than our best chain.\nChain state database "
                       "corruption likely.\n",
                       __func__);
             SetfLargeWorkInvalidChainFound(true);
         }
     } else {
         SetfLargeWorkForkFound(false);
         SetfLargeWorkInvalidChainFound(false);
     }
 }
 
 static void CheckForkWarningConditionsOnNewFork(CBlockIndex *pindexNewForkTip)
     EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
     AssertLockHeld(cs_main);
     // If we are on a fork that is sufficiently large, set a warning flag.
     const CBlockIndex *pfork = ::ChainActive().FindFork(pindexNewForkTip);
 
     // We define a condition where we should warn the user about as a fork of at
     // least 7 blocks with a tip within 72 blocks (+/- 12 hours if no one mines
     // it) of ours. We use 7 blocks rather arbitrarily as it represents just
     // under 10% of sustained network hash rate operating on the fork, or a
     // chain that is entirely longer than ours and invalid (note that this
     // should be detected by both). We define it this way because it allows us
     // to only store the highest fork tip (+ base) which meets the 7-block
     // condition and from this always have the most-likely-to-cause-warning fork
     if (pfork &&
         (!pindexBestForkTip ||
          pindexNewForkTip->nHeight > pindexBestForkTip->nHeight) &&
         pindexNewForkTip->nChainWork - pfork->nChainWork >
             (GetBlockProof(*pfork) * 7) &&
         ::ChainActive().Height() - pindexNewForkTip->nHeight < 72) {
         pindexBestForkTip = pindexNewForkTip;
         pindexBestForkBase = pfork;
     }
 
     CheckForkWarningConditions();
 }
 
 // Called both upon regular invalid block discovery *and* InvalidateBlock
 void CChainState::InvalidChainFound(CBlockIndex *pindexNew) {
     AssertLockHeld(cs_main);
     if (!pindexBestInvalid ||
         pindexNew->nChainWork > pindexBestInvalid->nChainWork) {
         pindexBestInvalid = pindexNew;
     }
     if (pindexBestHeader != nullptr &&
         pindexBestHeader->GetAncestor(pindexNew->nHeight) == pindexNew) {
         pindexBestHeader = ::ChainActive().Tip();
     }
 
     // If the invalid chain found is supposed to be finalized, we need to move
     // back the finalization point.
     if (IsBlockFinalized(pindexNew)) {
         m_finalizedBlockIndex = pindexNew->pprev;
     }
 
     LogPrintf("%s: invalid block=%s  height=%d  log2_work=%f  date=%s\n",
               __func__, pindexNew->GetBlockHash().ToString(),
               pindexNew->nHeight,
               log(pindexNew->nChainWork.getdouble()) / log(2.0),
               FormatISO8601DateTime(pindexNew->GetBlockTime()));
     CBlockIndex *tip = ::ChainActive().Tip();
     assert(tip);
     LogPrintf("%s:  current best=%s  height=%d  log2_work=%f  date=%s\n",
               __func__, tip->GetBlockHash().ToString(),
               ::ChainActive().Height(),
               log(tip->nChainWork.getdouble()) / log(2.0),
               FormatISO8601DateTime(tip->GetBlockTime()));
 }
 
 // Same as InvalidChainFound, above, except not called directly from
 // InvalidateBlock, which does its own setBlockIndexCandidates management.
 void CChainState::InvalidBlockFound(CBlockIndex *pindex,
                                     const BlockValidationState &state) {
     if (state.GetResult() != BlockValidationResult::BLOCK_MUTATED) {
         pindex->nStatus = pindex->nStatus.withFailed();
         m_blockman.m_failed_blocks.insert(pindex);
         setDirtyBlockIndex.insert(pindex);
         InvalidChainFound(pindex);
     }
 }
 
 void SpendCoins(CCoinsViewCache &view, const CTransaction &tx, CTxUndo &txundo,
                 int nHeight) {
     // Mark inputs spent.
     if (tx.IsCoinBase()) {
         return;
     }
 
     txundo.vprevout.reserve(tx.vin.size());
     for (const CTxIn &txin : tx.vin) {
         txundo.vprevout.emplace_back();
         bool is_spent = view.SpendCoin(txin.prevout, &txundo.vprevout.back());
         assert(is_spent);
     }
 }
 
 void UpdateCoins(CCoinsViewCache &view, const CTransaction &tx, CTxUndo &txundo,
                  int nHeight) {
     SpendCoins(view, tx, txundo, nHeight);
     AddCoins(view, tx, nHeight);
 }
 
 void UpdateCoins(CCoinsViewCache &view, const CTransaction &tx, int nHeight) {
     // Mark inputs spent.
     if (!tx.IsCoinBase()) {
         for (const CTxIn &txin : tx.vin) {
             bool is_spent = view.SpendCoin(txin.prevout);
             assert(is_spent);
         }
     }
 
     // Add outputs.
     AddCoins(view, tx, nHeight);
 }
 
 bool CScriptCheck::operator()() {
     const CScript &scriptSig = ptxTo->vin[nIn].scriptSig;
     if (!VerifyScript(scriptSig, m_tx_out.scriptPubKey, nFlags,
                       CachingTransactionSignatureChecker(
                           ptxTo, nIn, m_tx_out.nValue, cacheStore, txdata),
                       metrics, &error)) {
         return false;
     }
     if ((pTxLimitSigChecks &&
          !pTxLimitSigChecks->consume_and_check(metrics.nSigChecks)) ||
         (pBlockLimitSigChecks &&
          !pBlockLimitSigChecks->consume_and_check(metrics.nSigChecks))) {
         // we can't assign a meaningful script error (since the script
         // succeeded), but remove the ScriptError::OK which could be
         // misinterpreted.
         error = ScriptError::SIGCHECKS_LIMIT_EXCEEDED;
         return false;
     }
     return true;
 }
 
 int GetSpendHeight(const CCoinsViewCache &inputs) {
     LOCK(cs_main);
     CBlockIndex *pindexPrev = LookupBlockIndex(inputs.GetBestBlock());
     return pindexPrev->nHeight + 1;
 }
 
 bool CheckInputScripts(const CTransaction &tx, TxValidationState &state,
                        const CCoinsViewCache &inputs, const uint32_t flags,
                        bool sigCacheStore, bool scriptCacheStore,
                        const PrecomputedTransactionData &txdata,
                        int &nSigChecksOut, TxSigCheckLimiter &txLimitSigChecks,
                        CheckInputsLimiter *pBlockLimitSigChecks,
                        std::vector<CScriptCheck> *pvChecks) {
     AssertLockHeld(cs_main);
     assert(!tx.IsCoinBase());
 
     if (pvChecks) {
         pvChecks->reserve(tx.vin.size());
     }
 
     // First check if script executions have been cached with the same flags.
     // Note that this assumes that the inputs provided are correct (ie that the
     // transaction hash which is in tx's prevouts properly commits to the
     // scriptPubKey in the inputs view of that transaction).
     ScriptCacheKey hashCacheEntry(tx, flags);
     if (IsKeyInScriptCache(hashCacheEntry, !scriptCacheStore, nSigChecksOut)) {
         if (!txLimitSigChecks.consume_and_check(nSigChecksOut) ||
             (pBlockLimitSigChecks &&
              !pBlockLimitSigChecks->consume_and_check(nSigChecksOut))) {
             return state.Invalid(TxValidationResult::TX_CONSENSUS,
                                  "too-many-sigchecks");
         }
         return true;
     }
 
     int nSigChecksTotal = 0;
 
     for (size_t i = 0; i < tx.vin.size(); i++) {
         const COutPoint &prevout = tx.vin[i].prevout;
         const Coin &coin = inputs.AccessCoin(prevout);
         assert(!coin.IsSpent());
 
         // We very carefully only pass in things to CScriptCheck which are
         // clearly committed to by tx's hash. This provides a sanity
         // check that our caching is not introducing consensus failures through
         // additional data in, eg, the coins being spent being checked as a part
         // of CScriptCheck.
 
         // Verify signature
         CScriptCheck check(coin.GetTxOut(), tx, i, flags, sigCacheStore, txdata,
                            &txLimitSigChecks, pBlockLimitSigChecks);
 
         // If pvChecks is not null, defer the check execution to the caller.
         if (pvChecks) {
             pvChecks->push_back(std::move(check));
             continue;
         }
 
         if (!check()) {
             ScriptError scriptError = check.GetScriptError();
             // Compute flags without the optional standardness flags.
             // This differs from MANDATORY_SCRIPT_VERIFY_FLAGS as it contains
             // additional upgrade flags (see AcceptToMemoryPoolWorker variable
             // extraFlags).
             uint32_t mandatoryFlags =
                 flags & ~STANDARD_NOT_MANDATORY_VERIFY_FLAGS;
             if (flags != mandatoryFlags) {
                 // Check whether the failure was caused by a non-mandatory
                 // script verification check. If so, ensure we return
                 // NOT_STANDARD instead of CONSENSUS to avoid downstream users
                 // splitting the network between upgraded and non-upgraded nodes
                 // by banning CONSENSUS-failing data providers.
                 CScriptCheck check2(coin.GetTxOut(), tx, i, mandatoryFlags,
                                     sigCacheStore, txdata);
                 if (check2()) {
                     return state.Invalid(
                         TxValidationResult::TX_NOT_STANDARD,
                         strprintf("non-mandatory-script-verify-flag (%s)",
                                   ScriptErrorString(scriptError)));
                 }
                 // update the error message to reflect the mandatory violation.
                 scriptError = check2.GetScriptError();
             }
 
             // MANDATORY flag failures correspond to
             // TxValidationResult::TX_CONSENSUS. Because CONSENSUS failures are
             // the most serious case of validation failures, we may need to
             // consider using RECENT_CONSENSUS_CHANGE for any script failure
             // that could be due to non-upgraded nodes which we may want to
             // support, to avoid splitting the network (but this depends on the
             // details of how net_processing handles such errors).
             return state.Invalid(
                 TxValidationResult::TX_CONSENSUS,
                 strprintf("mandatory-script-verify-flag-failed (%s)",
                           ScriptErrorString(scriptError)));
         }
 
         nSigChecksTotal += check.GetScriptExecutionMetrics().nSigChecks;
     }
 
     nSigChecksOut = nSigChecksTotal;
 
     if (scriptCacheStore && !pvChecks) {
         // We executed all of the provided scripts, and were told to cache the
         // result. Do so now.
         AddKeyInScriptCache(hashCacheEntry, nSigChecksTotal);
     }
 
     return true;
 }
 
 static bool UndoWriteToDisk(const CBlockUndo &blockundo, FlatFilePos &pos,
                             const BlockHash &hashBlock,
                             const CMessageHeader::MessageMagic &messageStart) {
     // Open history file to append
     CAutoFile fileout(OpenUndoFile(pos), SER_DISK, CLIENT_VERSION);
     if (fileout.IsNull()) {
         return error("%s: OpenUndoFile failed", __func__);
     }
 
     // Write index header
     unsigned int nSize = GetSerializeSize(blockundo, fileout.GetVersion());
     fileout << messageStart << nSize;
 
     // Write undo data
     long fileOutPos = ftell(fileout.Get());
     if (fileOutPos < 0) {
         return error("%s: ftell failed", __func__);
     }
     pos.nPos = (unsigned int)fileOutPos;
     fileout << blockundo;
 
     // calculate & write checksum
     CHashWriter hasher(SER_GETHASH, PROTOCOL_VERSION);
     hasher << hashBlock;
     hasher << blockundo;
     fileout << hasher.GetHash();
 
     return true;
 }
 
 bool UndoReadFromDisk(CBlockUndo &blockundo, const CBlockIndex *pindex) {
     FlatFilePos pos = pindex->GetUndoPos();
     if (pos.IsNull()) {
         return error("%s: no undo data available", __func__);
     }
 
     // Open history file to read
     CAutoFile filein(OpenUndoFile(pos, true), SER_DISK, CLIENT_VERSION);
     if (filein.IsNull()) {
         return error("%s: OpenUndoFile failed", __func__);
     }
 
     // Read block
     uint256 hashChecksum;
     // We need a CHashVerifier as reserializing may lose data
     CHashVerifier<CAutoFile> verifier(&filein);
     try {
         verifier << pindex->pprev->GetBlockHash();
         verifier >> blockundo;
         filein >> hashChecksum;
     } catch (const std::exception &e) {
         return error("%s: Deserialize or I/O error - %s", __func__, e.what());
     }
 
     // Verify checksum
     if (hashChecksum != verifier.GetHash()) {
         return error("%s: Checksum mismatch", __func__);
     }
 
     return true;
 }
 
 /** Abort with a message */
 static bool AbortNode(const std::string &strMessage,
                       bilingual_str user_message = bilingual_str()) {
     SetMiscWarning(Untranslated(strMessage));
     LogPrintf("*** %s\n", strMessage);
     if (!user_message.empty()) {
         user_message =
             _("A fatal internal error occurred, see debug.log for details");
     }
     AbortError(user_message);
     StartShutdown();
     return false;
 }
 
 static bool AbortNode(BlockValidationState &state,
                       const std::string &strMessage,
                       const bilingual_str &userMessage = bilingual_str()) {
     AbortNode(strMessage, userMessage);
     return state.Error(strMessage);
 }
 
 /** Restore the UTXO in a Coin at a given COutPoint. */
 DisconnectResult UndoCoinSpend(const Coin &undo, CCoinsViewCache &view,
                                const COutPoint &out) {
     bool fClean = true;
 
     if (view.HaveCoin(out)) {
         // Overwriting transaction output.
         fClean = false;
     }
 
     if (undo.GetHeight() == 0) {
         // Missing undo metadata (height and coinbase). Older versions included
         // this information only in undo records for the last spend of a
         // transactions' outputs. This implies that it must be present for some
         // other output of the same tx.
         const Coin &alternate = AccessByTxid(view, out.GetTxId());
         if (alternate.IsSpent()) {
             // Adding output for transaction without known metadata
             return DisconnectResult::FAILED;
         }
 
         // This is somewhat ugly, but hopefully utility is limited. This is only
         // useful when working from legacy on disck data. In any case, putting
         // the correct information in there doesn't hurt.
         const_cast<Coin &>(undo) = Coin(undo.GetTxOut(), alternate.GetHeight(),
                                         alternate.IsCoinBase());
     }
 
     // If the coin already exists as an unspent coin in the cache, then the
     // possible_overwrite parameter to AddCoin must be set to true. We have
     // already checked whether an unspent coin exists above using HaveCoin, so
     // we don't need to guess. When fClean is false, an unspent coin already
     // existed and it is an overwrite.
     view.AddCoin(out, std::move(undo), !fClean);
 
     return fClean ? DisconnectResult::OK : DisconnectResult::UNCLEAN;
 }
 
 /**
  * Undo the effects of this block (with given index) on the UTXO set represented
  * by coins. When FAILED is returned, view is left in an indeterminate state.
  */
 DisconnectResult CChainState::DisconnectBlock(const CBlock &block,
                                               const CBlockIndex *pindex,
                                               CCoinsViewCache &view) {
     CBlockUndo blockUndo;
     if (!UndoReadFromDisk(blockUndo, pindex)) {
         error("DisconnectBlock(): failure reading undo data");
         return DisconnectResult::FAILED;
     }
 
     return ApplyBlockUndo(blockUndo, block, pindex, view);
 }
 
 DisconnectResult ApplyBlockUndo(const CBlockUndo &blockUndo,
                                 const CBlock &block, const CBlockIndex *pindex,
                                 CCoinsViewCache &view) {
     bool fClean = true;
 
     if (blockUndo.vtxundo.size() + 1 != block.vtx.size()) {
         error("DisconnectBlock(): block and undo data inconsistent");
         return DisconnectResult::FAILED;
     }
 
     // First, restore inputs.
     for (size_t i = 1; i < block.vtx.size(); i++) {
         const CTransaction &tx = *(block.vtx[i]);
         const CTxUndo &txundo = blockUndo.vtxundo[i - 1];
         if (txundo.vprevout.size() != tx.vin.size()) {
             error("DisconnectBlock(): transaction and undo data inconsistent");
             return DisconnectResult::FAILED;
         }
 
         for (size_t j = 0; j < tx.vin.size(); j++) {
             const COutPoint &out = tx.vin[j].prevout;
             const Coin &undo = txundo.vprevout[j];
             DisconnectResult res = UndoCoinSpend(undo, view, out);
             if (res == DisconnectResult::FAILED) {
                 return DisconnectResult::FAILED;
             }
             fClean = fClean && res != DisconnectResult::UNCLEAN;
         }
     }
 
     // Second, revert created outputs.
     for (const auto &ptx : block.vtx) {
         const CTransaction &tx = *ptx;
         const TxId &txid = tx.GetId();
         const bool is_coinbase = tx.IsCoinBase();
 
         // Check that all outputs are available and match the outputs in the
         // block itself exactly.
         for (size_t o = 0; o < tx.vout.size(); o++) {
             if (tx.vout[o].scriptPubKey.IsUnspendable()) {
                 continue;
             }
 
             COutPoint out(txid, o);
             Coin coin;
             bool is_spent = view.SpendCoin(out, &coin);
             if (!is_spent || tx.vout[o] != coin.GetTxOut() ||
                 uint32_t(pindex->nHeight) != coin.GetHeight() ||
                 is_coinbase != coin.IsCoinBase()) {
                 // transaction output mismatch
                 fClean = false;
             }
         }
     }
 
     // Move best block pointer to previous block.
     view.SetBestBlock(block.hashPrevBlock);
 
     return fClean ? DisconnectResult::OK : DisconnectResult::UNCLEAN;
 }
 
 static void FlushUndoFile(int block_file, bool finalize = false) {
     FlatFilePos undo_pos_old(block_file, vinfoBlockFile[block_file].nUndoSize);
     if (!UndoFileSeq().Flush(undo_pos_old, finalize)) {
         AbortNode("Flushing undo file to disk failed. This is likely the "
                   "result of an I/O error.");
     }
 }
 
 static void FlushBlockFile(bool fFinalize = false, bool finalize_undo = false) {
     LOCK(cs_LastBlockFile);
     FlatFilePos block_pos_old(nLastBlockFile,
                               vinfoBlockFile[nLastBlockFile].nSize);
     if (!BlockFileSeq().Flush(block_pos_old, fFinalize)) {
         AbortNode("Flushing block file to disk failed. This is likely the "
                   "result of an I/O error.");
     }
     // we do not always flush the undo file, as the chain tip may be lagging
     // behind the incoming blocks,
     // e.g. during IBD or a sync after a node going offline
     if (!fFinalize || finalize_undo) {
         FlushUndoFile(nLastBlockFile, finalize_undo);
     }
 }
 
 static bool FindUndoPos(BlockValidationState &state, int nFile,
                         FlatFilePos &pos, unsigned int nAddSize);
 
 static bool WriteUndoDataForBlock(const CBlockUndo &blockundo,
                                   BlockValidationState &state,
                                   CBlockIndex *pindex,
                                   const CChainParams &chainparams) {
     // Write undo information to disk
     if (pindex->GetUndoPos().IsNull()) {
         FlatFilePos _pos;
         if (!FindUndoPos(state, pindex->nFile, _pos,
                          ::GetSerializeSize(blockundo, CLIENT_VERSION) + 40)) {
             return error("ConnectBlock(): FindUndoPos failed");
         }
         if (!UndoWriteToDisk(blockundo, _pos, pindex->pprev->GetBlockHash(),
                              chainparams.DiskMagic())) {
             return AbortNode(state, "Failed to write undo data");
         }
         // rev files are written in block height order, whereas blk files are
         // written as blocks come in (often out of order) we want to flush the
         // rev (undo) file once we've written the last block, which is indicated
         // by the last height in the block file info as below; note that this
         // does not catch the case where the undo writes are keeping up with the
         // block writes (usually when a synced up node is getting newly mined
         // blocks) -- this case is caught in the FindBlockPos function
         if (_pos.nFile < nLastBlockFile &&
             static_cast<uint32_t>(pindex->nHeight) ==
                 vinfoBlockFile[_pos.nFile].nHeightLast) {
             FlushUndoFile(_pos.nFile, true);
         }
 
         // update nUndoPos in block index
         pindex->nUndoPos = _pos.nPos;
         pindex->nStatus = pindex->nStatus.withUndo();
         setDirtyBlockIndex.insert(pindex);
     }
 
     return true;
 }
 
 static CCheckQueue<CScriptCheck> scriptcheckqueue(128);
 
 void ThreadScriptCheck(int worker_num) {
     util::ThreadRename(strprintf("scriptch.%i", worker_num));
     scriptcheckqueue.Thread();
 }
 
 VersionBitsCache versionbitscache GUARDED_BY(cs_main);
 
 int32_t ComputeBlockVersion(const CBlockIndex *pindexPrev,
                             const Consensus::Params &params) {
     LOCK(cs_main);
     int32_t nVersion = VERSIONBITS_TOP_BITS;
 
     for (int i = 0; i < (int)Consensus::MAX_VERSION_BITS_DEPLOYMENTS; i++) {
         ThresholdState state = VersionBitsState(
             pindexPrev, params, static_cast<Consensus::DeploymentPos>(i),
             versionbitscache);
         if (state == ThresholdState::LOCKED_IN ||
             state == ThresholdState::STARTED) {
             nVersion |= VersionBitsMask(
                 params, static_cast<Consensus::DeploymentPos>(i));
         }
     }
 
     // Clear the last 4 bits (miner fund activation).
     return nVersion & ~uint32_t(0x0f);
 }
 
 // Returns the script flags which should be checked for the block after
 // the given block.
 static uint32_t GetNextBlockScriptFlags(const Consensus::Params &params,
                                         const CBlockIndex *pindex) {
     uint32_t flags = SCRIPT_VERIFY_NONE;
 
     // Start enforcing P2SH (BIP16)
     if ((pindex->nHeight + 1) >= params.BIP16Height) {
         flags |= SCRIPT_VERIFY_P2SH;
     }
 
     // Start enforcing the DERSIG (BIP66) rule.
     if ((pindex->nHeight + 1) >= params.BIP66Height) {
         flags |= SCRIPT_VERIFY_DERSIG;
     }
 
     // Start enforcing CHECKLOCKTIMEVERIFY (BIP65) rule.
     if ((pindex->nHeight + 1) >= params.BIP65Height) {
         flags |= SCRIPT_VERIFY_CHECKLOCKTIMEVERIFY;
     }
 
     // Start enforcing CSV (BIP68, BIP112 and BIP113) rule.
     if ((pindex->nHeight + 1) >= params.CSVHeight) {
         flags |= SCRIPT_VERIFY_CHECKSEQUENCEVERIFY;
     }
 
     // If the UAHF is enabled, we start accepting replay protected txns
     if (IsUAHFenabled(params, pindex)) {
         flags |= SCRIPT_VERIFY_STRICTENC;
         flags |= SCRIPT_ENABLE_SIGHASH_FORKID;
     }
 
     // If the DAA HF is enabled, we start rejecting transaction that use a high
     // s in their signature. We also make sure that signature that are supposed
     // to fail (for instance in multisig or other forms of smart contracts) are
     // null.
     if (IsDAAEnabled(params, pindex)) {
         flags |= SCRIPT_VERIFY_LOW_S;
         flags |= SCRIPT_VERIFY_NULLFAIL;
     }
 
     // When the magnetic anomaly fork is enabled, we start accepting
     // transactions using the OP_CHECKDATASIG opcode and it's verify
     // alternative. We also start enforcing push only signatures and
     // clean stack.
     if (IsMagneticAnomalyEnabled(params, pindex)) {
         flags |= SCRIPT_VERIFY_CHECKDATASIG_SIGOPS;
         flags |= SCRIPT_VERIFY_SIGPUSHONLY;
         flags |= SCRIPT_VERIFY_CLEANSTACK;
     }
 
     if (IsGravitonEnabled(params, pindex)) {
         flags |= SCRIPT_ENABLE_SCHNORR_MULTISIG;
         flags |= SCRIPT_VERIFY_MINIMALDATA;
     }
 
     if (IsPhononEnabled(params, pindex)) {
         flags |= SCRIPT_ENFORCE_SIGCHECKS;
     }
 
     // We make sure this node will have replay protection during the next hard
     // fork.
     if (IsReplayProtectionEnabled(params, pindex)) {
         flags |= SCRIPT_ENABLE_REPLAY_PROTECTION;
     }
 
     return flags;
 }
 
 static int64_t nTimeCheck = 0;
 static int64_t nTimeForks = 0;
 static int64_t nTimeVerify = 0;
 static int64_t nTimeConnect = 0;
 static int64_t nTimeIndex = 0;
 static int64_t nTimeCallbacks = 0;
 static int64_t nTimeTotal = 0;
 static int64_t nBlocksTotal = 0;
 
 /**
  * Apply the effects of this block (with given index) on the UTXO set
  * represented by coins. Validity checks that depend on the UTXO set are also
  * done; ConnectBlock() can fail if those validity checks fail (among other
  * reasons).
  */
 bool CChainState::ConnectBlock(const CBlock &block, BlockValidationState &state,
                                CBlockIndex *pindex, CCoinsViewCache &view,
                                const CChainParams &params,
                                BlockValidationOptions options,
                                bool fJustCheck) {
     AssertLockHeld(cs_main);
     assert(pindex);
     assert(*pindex->phashBlock == block.GetHash());
     int64_t nTimeStart = GetTimeMicros();
 
     const Consensus::Params &consensusParams = params.GetConsensus();
 
     // Check it again in case a previous version let a bad block in
     // NOTE: We don't currently (re-)invoke ContextualCheckBlock() or
     // ContextualCheckBlockHeader() here. This means that if we add a new
     // consensus rule that is enforced in one of those two functions, then we
     // may have let in a block that violates the rule prior to updating the
     // software, and we would NOT be enforcing the rule here. Fully solving
     // upgrade from one software version to the next after a consensus rule
     // change is potentially tricky and issue-specific.
     // Also, currently the rule against blocks more than 2 hours in the future
     // is enforced in ContextualCheckBlockHeader(); we wouldn't want to
     // re-enforce that rule here (at least until we make it impossible for
     // GetAdjustedTime() to go backward).
     if (!CheckBlock(block, state, consensusParams,
                     options.withCheckPoW(!fJustCheck)
                         .withCheckMerkleRoot(!fJustCheck))) {
         if (state.GetResult() == BlockValidationResult::BLOCK_MUTATED) {
             // We don't write down blocks to disk if they may have been
             // corrupted, so this should be impossible unless we're having
             // hardware problems.
             return AbortNode(state, "Corrupt block found indicating potential "
                                     "hardware failure; shutting down");
         }
         return error("%s: Consensus::CheckBlock: %s", __func__,
                      state.ToString());
     }
 
     // Verify that the view's current state corresponds to the previous block
     BlockHash hashPrevBlock =
         pindex->pprev == nullptr ? BlockHash() : pindex->pprev->GetBlockHash();
     assert(hashPrevBlock == view.GetBestBlock());
 
     nBlocksTotal++;
 
     // Special case for the genesis block, skipping connection of its
     // transactions (its coinbase is unspendable)
     if (block.GetHash() == consensusParams.hashGenesisBlock) {
         if (!fJustCheck) {
             view.SetBestBlock(pindex->GetBlockHash());
         }
 
         return true;
     }
 
     bool fScriptChecks = true;
     if (!hashAssumeValid.IsNull()) {
         // We've been configured with the hash of a block which has been
         // externally verified to have a valid history. A suitable default value
         // is included with the software and updated from time to time. Because
         // validity relative to a piece of software is an objective fact these
         // defaults can be easily reviewed. This setting doesn't force the
         // selection of any particular chain but makes validating some faster by
         // effectively caching the result of part of the verification.
         BlockMap::const_iterator it =
             m_blockman.m_block_index.find(hashAssumeValid);
         if (it != m_blockman.m_block_index.end()) {
             if (it->second->GetAncestor(pindex->nHeight) == pindex &&
                 pindexBestHeader->GetAncestor(pindex->nHeight) == pindex &&
                 pindexBestHeader->nChainWork >= nMinimumChainWork) {
                 // This block is a member of the assumed verified chain and an
                 // ancestor of the best header.
                 // Script verification is skipped when connecting blocks under
                 // the assumevalid block. Assuming the assumevalid block is
                 // valid this is safe because block merkle hashes are still
                 // computed and checked, Of course, if an assumed valid block is
                 // invalid due to false scriptSigs this optimization would allow
                 // an invalid chain to be accepted.
                 // The equivalent time check discourages hash power from
                 // extorting the network via DOS attack into accepting an
                 // invalid block through telling users they must manually set
                 // assumevalid. Requiring a software change or burying the
                 // invalid block, regardless of the setting, makes it hard to
                 // hide the implication of the demand. This also avoids having
                 // release candidates that are hardly doing any signature
                 // verification at all in testing without having to artificially
                 // set the default assumed verified block further back. The test
                 // against nMinimumChainWork prevents the skipping when denied
                 // access to any chain at least as good as the expected chain.
                 fScriptChecks =
                     (GetBlockProofEquivalentTime(
                          *pindexBestHeader, *pindex, *pindexBestHeader,
                          consensusParams) <= 60 * 60 * 24 * 7 * 2);
             }
         }
     }
 
     int64_t nTime1 = GetTimeMicros();
     nTimeCheck += nTime1 - nTimeStart;
     LogPrint(BCLog::BENCH, "    - Sanity checks: %.2fms [%.2fs (%.2fms/blk)]\n",
              MILLI * (nTime1 - nTimeStart), nTimeCheck * MICRO,
              nTimeCheck * MILLI / nBlocksTotal);
 
     // Do not allow blocks that contain transactions which 'overwrite' older
     // transactions, unless those are already completely spent. If such
     // overwrites are allowed, coinbases and transactions depending upon those
     // can be duplicated to remove the ability to spend the first instance --
     // even after being sent to another address.
     // See BIP30, CVE-2012-1909, and http://r6.ca/blog/20120206T005236Z.html
     // for more information. This logic is not necessary for memory pool
     // transactions, as AcceptToMemoryPool already refuses previously-known
     // transaction ids entirely. This rule was originally applied to all blocks
     // with a timestamp after March 15, 2012, 0:00 UTC. Now that the whole
     // chain is irreversibly beyond that time it is applied to all blocks
     // except the two in the chain that violate it. This prevents exploiting
     // the issue against nodes during their initial block download.
     bool fEnforceBIP30 = !((pindex->nHeight == 91842 &&
                             pindex->GetBlockHash() ==
                                 uint256S("0x00000000000a4d0a398161ffc163c503763"
                                          "b1f4360639393e0e4c8e300e0caec")) ||
                            (pindex->nHeight == 91880 &&
                             pindex->GetBlockHash() ==
                                 uint256S("0x00000000000743f190a18c5577a3c2d2a1f"
                                          "610ae9601ac046a38084ccb7cd721")));
 
     // Once BIP34 activated it was not possible to create new duplicate
     // coinbases and thus other than starting with the 2 existing duplicate
     // coinbase pairs, not possible to create overwriting txs. But by the time
     // BIP34 activated, in each of the existing pairs the duplicate coinbase had
     // overwritten the first before the first had been spent. Since those
     // coinbases are sufficiently buried it's no longer possible to create
     // further duplicate transactions descending from the known pairs either. If
     // we're on the known chain at height greater than where BIP34 activated, we
     // can save the db accesses needed for the BIP30 check.
 
     // BIP34 requires that a block at height X (block X) has its coinbase
     // scriptSig start with a CScriptNum of X (indicated height X).  The above
     // logic of no longer requiring BIP30 once BIP34 activates is flawed in the
     // case that there is a block X before the BIP34 height of 227,931 which has
     // an indicated height Y where Y is greater than X.  The coinbase for block
     // X would also be a valid coinbase for block Y, which could be a BIP30
     // violation.  An exhaustive search of all mainnet coinbases before the
     // BIP34 height which have an indicated height greater than the block height
     // reveals many occurrences. The 3 lowest indicated heights found are
     // 209,921, 490,897, and 1,983,702 and thus coinbases for blocks at these 3
     // heights would be the first opportunity for BIP30 to be violated.
 
     // The search reveals a great many blocks which have an indicated height
     // greater than 1,983,702, so we simply remove the optimization to skip
     // BIP30 checking for blocks at height 1,983,702 or higher.  Before we reach
     // that block in another 25 years or so, we should take advantage of a
     // future consensus change to do a new and improved version of BIP34 that
     // will actually prevent ever creating any duplicate coinbases in the
     // future.
     static constexpr int BIP34_IMPLIES_BIP30_LIMIT = 1983702;
 
     // There is no potential to create a duplicate coinbase at block 209,921
     // because this is still before the BIP34 height and so explicit BIP30
     // checking is still active.
 
     // The final case is block 176,684 which has an indicated height of
     // 490,897. Unfortunately, this issue was not discovered until about 2 weeks
     // before block 490,897 so there was not much opportunity to address this
     // case other than to carefully analyze it and determine it would not be a
     // problem. Block 490,897 was, in fact, mined with a different coinbase than
     // block 176,684, but it is important to note that even if it hadn't been or
     // is remined on an alternate fork with a duplicate coinbase, we would still
     // not run into a BIP30 violation.  This is because the coinbase for 176,684
     // is spent in block 185,956 in transaction
     // d4f7fbbf92f4a3014a230b2dc70b8058d02eb36ac06b4a0736d9d60eaa9e8781.  This
     // spending transaction can't be duplicated because it also spends coinbase
     // 0328dd85c331237f18e781d692c92de57649529bd5edf1d01036daea32ffde29.  This
     // coinbase has an indicated height of over 4.2 billion, and wouldn't be
     // duplicatable until that height, and it's currently impossible to create a
     // chain that long. Nevertheless we may wish to consider a future soft fork
     // which retroactively prevents block 490,897 from creating a duplicate
     // coinbase. The two historical BIP30 violations often provide a confusing
     // edge case when manipulating the UTXO and it would be simpler not to have
     // another edge case to deal with.
 
     // testnet3 has no blocks before the BIP34 height with indicated heights
     // post BIP34 before approximately height 486,000,000 and presumably will
     // be reset before it reaches block 1,983,702 and starts doing unnecessary
     // BIP30 checking again.
     assert(pindex->pprev);
     CBlockIndex *pindexBIP34height =
         pindex->pprev->GetAncestor(consensusParams.BIP34Height);
     // Only continue to enforce if we're below BIP34 activation height or the
     // block hash at that height doesn't correspond.
     fEnforceBIP30 =
         fEnforceBIP30 &&
         (!pindexBIP34height ||
          !(pindexBIP34height->GetBlockHash() == consensusParams.BIP34Hash));
 
     // TODO: Remove BIP30 checking from block height 1,983,702 on, once we have
     // a consensus change that ensures coinbases at those heights can not
     // duplicate earlier coinbases.
     if (fEnforceBIP30 || pindex->nHeight >= BIP34_IMPLIES_BIP30_LIMIT) {
         for (const auto &tx : block.vtx) {
             for (size_t o = 0; o < tx->vout.size(); o++) {
                 if (view.HaveCoin(COutPoint(tx->GetId(), o))) {
                     LogPrintf("ERROR: ConnectBlock(): tried to overwrite "
                               "transaction\n");
                     return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS,
                                          "bad-txns-BIP30");
                 }
             }
         }
     }
 
     // Start enforcing BIP68 (sequence locks).
     int nLockTimeFlags = 0;
     if (pindex->nHeight >= consensusParams.CSVHeight) {
         nLockTimeFlags |= LOCKTIME_VERIFY_SEQUENCE;
     }
 
     const uint32_t flags =
         GetNextBlockScriptFlags(consensusParams, pindex->pprev);
 
     int64_t nTime2 = GetTimeMicros();
     nTimeForks += nTime2 - nTime1;
     LogPrint(BCLog::BENCH, "    - Fork checks: %.2fms [%.2fs (%.2fms/blk)]\n",
              MILLI * (nTime2 - nTime1), nTimeForks * MICRO,
              nTimeForks * MILLI / nBlocksTotal);
 
     std::vector<int> prevheights;
     Amount nFees = Amount::zero();
     int nInputs = 0;
 
     // Limit the total executed signature operations in the block, a consensus
     // rule. Tracking during the CPU-consuming part (validation of uncached
     // inputs) is per-input atomic and validation in each thread stops very
     // quickly after the limit is exceeded, so an adversary cannot cause us to
     // exceed the limit by much at all.
     CheckInputsLimiter nSigChecksBlockLimiter(
         GetMaxBlockSigChecksCount(options.getExcessiveBlockSize()));
 
     std::vector<TxSigCheckLimiter> nSigChecksTxLimiters;
     nSigChecksTxLimiters.resize(block.vtx.size() - 1);
 
     CBlockUndo blockundo;
     blockundo.vtxundo.resize(block.vtx.size() - 1);
 
     CCheckQueueControl<CScriptCheck> control(fScriptChecks ? &scriptcheckqueue
                                                            : nullptr);
 
     // Add all outputs
     try {
         for (const auto &ptx : block.vtx) {
             AddCoins(view, *ptx, pindex->nHeight);
         }
     } catch (const std::logic_error &e) {
         // This error will be thrown from AddCoin if we try to connect a block
         // containing duplicate transactions. Such a thing should normally be
         // caught early nowadays (due to ContextualCheckBlock's CTOR
         // enforcement) however some edge cases can escape that:
         // - ContextualCheckBlock does not get re-run after saving the block to
         // disk, and older versions may have saved a weird block.
         // - its checks are not applied to pre-CTOR chains, which we might visit
         // with checkpointing off.
         LogPrintf("ERROR: ConnectBlock(): tried to overwrite transaction\n");
         return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS,
                              "tx-duplicate");
     }
 
     size_t txIndex = 0;
     for (const auto &ptx : block.vtx) {
         const CTransaction &tx = *ptx;
         const bool isCoinBase = tx.IsCoinBase();
         nInputs += tx.vin.size();
 
         {
             Amount txfee = Amount::zero();
             TxValidationState tx_state;
             if (!isCoinBase &&
                 !Consensus::CheckTxInputs(tx, tx_state, view, pindex->nHeight,
                                           txfee)) {
                 // Any transaction validation failure in ConnectBlock is a block
                 // consensus failure.
                 state.Invalid(BlockValidationResult::BLOCK_CONSENSUS,
                               tx_state.GetRejectReason(),
                               tx_state.GetDebugMessage());
 
                 return error("%s: Consensus::CheckTxInputs: %s, %s", __func__,
                              tx.GetId().ToString(), state.ToString());
             }
             nFees += txfee;
         }
 
         if (!MoneyRange(nFees)) {
             LogPrintf("ERROR: %s: accumulated fee in the block out of range.\n",
                       __func__);
             return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS,
                                  "bad-txns-accumulated-fee-outofrange");
         }
 
         // The following checks do not apply to the coinbase.
         if (isCoinBase) {
             continue;
         }
 
         // Check that transaction is BIP68 final BIP68 lock checks (as
         // opposed to nLockTime checks) must be in ConnectBlock because they
         // require the UTXO set.
         prevheights.resize(tx.vin.size());
         for (size_t j = 0; j < tx.vin.size(); j++) {
             prevheights[j] = view.AccessCoin(tx.vin[j].prevout).GetHeight();
         }
 
         if (!SequenceLocks(tx, nLockTimeFlags, prevheights, *pindex)) {
             LogPrintf("ERROR: %s: contains a non-BIP68-final transaction\n",
                       __func__);
             return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS,
                                  "bad-txns-nonfinal");
         }
 
         // Don't cache results if we're actually connecting blocks (still
         // consult the cache, though).
         bool fCacheResults = fJustCheck;
 
         const bool fEnforceSigCheck = flags & SCRIPT_ENFORCE_SIGCHECKS;
         if (!fEnforceSigCheck) {
             // Historically, there has been transactions with a very high
             // sigcheck count, so we need to disable this check for such
             // transactions.
             nSigChecksTxLimiters[txIndex] = TxSigCheckLimiter::getDisabled();
         }
 
         std::vector<CScriptCheck> vChecks;
         // nSigChecksRet may be accurate (found in cache) or 0 (checks were
         // deferred into vChecks).
         int nSigChecksRet;
         TxValidationState tx_state;
         if (fScriptChecks &&
             !CheckInputScripts(tx, tx_state, view, flags, fCacheResults,
                                fCacheResults, PrecomputedTransactionData(tx),
                                nSigChecksRet, nSigChecksTxLimiters[txIndex],
                                &nSigChecksBlockLimiter, &vChecks)) {
             // Any transaction validation failure in ConnectBlock is a block
             // consensus failure
             state.Invalid(BlockValidationResult::BLOCK_CONSENSUS,
                           tx_state.GetRejectReason(),
                           tx_state.GetDebugMessage());
             return error(
                 "ConnectBlock(): CheckInputScripts on %s failed with %s",
                 tx.GetId().ToString(), state.ToString());
         }
 
         control.Add(vChecks);
 
         // Note: this must execute in the same iteration as CheckTxInputs (not
         // in a separate loop) in order to detect double spends. However,
         // this does not prevent double-spending by duplicated transaction
         // inputs in the same transaction (cf. CVE-2018-17144) -- that check is
         // done in CheckBlock (CheckRegularTransaction).
         SpendCoins(view, tx, blockundo.vtxundo.at(txIndex), pindex->nHeight);
         txIndex++;
     }
 
     int64_t nTime3 = GetTimeMicros();
     nTimeConnect += nTime3 - nTime2;
     LogPrint(BCLog::BENCH,
              "      - Connect %u transactions: %.2fms (%.3fms/tx, %.3fms/txin) "
              "[%.2fs (%.2fms/blk)]\n",
              (unsigned)block.vtx.size(), MILLI * (nTime3 - nTime2),
              MILLI * (nTime3 - nTime2) / block.vtx.size(),
              nInputs <= 1 ? 0 : MILLI * (nTime3 - nTime2) / (nInputs - 1),
              nTimeConnect * MICRO, nTimeConnect * MILLI / nBlocksTotal);
 
     Amount blockReward =
         nFees + GetBlockSubsidy(pindex->nHeight, consensusParams);
     if (block.vtx[0]->GetValueOut() > blockReward) {
         LogPrintf("ERROR: ConnectBlock(): coinbase pays too much (actual=%d vs "
                   "limit=%d)\n",
                   block.vtx[0]->GetValueOut(), blockReward);
         return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS,
                              "bad-cb-amount");
     }
 
     const std::vector<CTxDestination> whitelist =
         GetMinerFundWhitelist(consensusParams, pindex->pprev);
     if (!whitelist.empty()) {
         const Amount required = GetMinerFundAmount(blockReward);
 
         for (auto &o : block.vtx[0]->vout) {
             if (o.nValue < required) {
                 // This output doesn't qualify because its amount is too low.
                 continue;
             }
 
             CTxDestination address;
             if (!ExtractDestination(o.scriptPubKey, address)) {
                 // Cannot decode address.
                 continue;
             }
 
             if (std::find(whitelist.begin(), whitelist.end(), address) !=
                 whitelist.end()) {
                 goto MinerFundSuccess;
             }
         }
 
         // We did not find an output that match the miner fund requirements.
         return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS,
                              "bad-cb-minerfund");
     }
 
 MinerFundSuccess:
 
     if (!control.Wait()) {
         return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS,
                              "blk-bad-inputs", "parallel script check failed");
     }
 
     int64_t nTime4 = GetTimeMicros();
     nTimeVerify += nTime4 - nTime2;
     LogPrint(
         BCLog::BENCH,
         "    - Verify %u txins: %.2fms (%.3fms/txin) [%.2fs (%.2fms/blk)]\n",
         nInputs - 1, MILLI * (nTime4 - nTime2),
         nInputs <= 1 ? 0 : MILLI * (nTime4 - nTime2) / (nInputs - 1),
         nTimeVerify * MICRO, nTimeVerify * MILLI / nBlocksTotal);
 
     if (fJustCheck) {
         return true;
     }
 
     if (!WriteUndoDataForBlock(blockundo, state, pindex, params)) {
         return false;
     }
 
     if (!pindex->IsValid(BlockValidity::SCRIPTS)) {
         pindex->RaiseValidity(BlockValidity::SCRIPTS);
         setDirtyBlockIndex.insert(pindex);
     }
 
     assert(pindex->phashBlock);
     // add this block to the view's block chain
     view.SetBestBlock(pindex->GetBlockHash());
 
     int64_t nTime5 = GetTimeMicros();
     nTimeIndex += nTime5 - nTime4;
     LogPrint(BCLog::BENCH, "    - Index writing: %.2fms [%.2fs (%.2fms/blk)]\n",
              MILLI * (nTime5 - nTime4), nTimeIndex * MICRO,
              nTimeIndex * MILLI / nBlocksTotal);
 
     int64_t nTime6 = GetTimeMicros();
     nTimeCallbacks += nTime6 - nTime5;
     LogPrint(BCLog::BENCH, "    - Callbacks: %.2fms [%.2fs (%.2fms/blk)]\n",
              MILLI * (nTime6 - nTime5), nTimeCallbacks * MICRO,
              nTimeCallbacks * MILLI / nBlocksTotal);
 
     return true;
 }
 
 CoinsCacheSizeState
 CChainState::GetCoinsCacheSizeState(const CTxMemPool *tx_pool) {
     return this->GetCoinsCacheSizeState(
         tx_pool, m_coinstip_cache_size_bytes,
         gArgs.GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000);
 }
 
 CoinsCacheSizeState
 CChainState::GetCoinsCacheSizeState(const CTxMemPool *tx_pool,
                                     size_t max_coins_cache_size_bytes,
                                     size_t max_mempool_size_bytes) {
     int64_t nMempoolUsage = tx_pool->DynamicMemoryUsage();
     int64_t cacheSize = CoinsTip().DynamicMemoryUsage();
     int64_t nTotalSpace =
         max_coins_cache_size_bytes +
         std::max<int64_t>(max_mempool_size_bytes - nMempoolUsage, 0);
 
     //! No need to periodic flush if at least this much space still available.
     static constexpr int64_t MAX_BLOCK_COINSDB_USAGE_BYTES =
         10 * 1024 * 1024; // 10MB
     int64_t large_threshold = std::max(
         (9 * nTotalSpace) / 10, nTotalSpace - MAX_BLOCK_COINSDB_USAGE_BYTES);
 
     if (cacheSize > nTotalSpace) {
         LogPrintf("Cache size (%s) exceeds total space (%s)\n", cacheSize,
                   nTotalSpace);
         return CoinsCacheSizeState::CRITICAL;
     } else if (cacheSize > large_threshold) {
         return CoinsCacheSizeState::LARGE;
     }
     return CoinsCacheSizeState::OK;
 }
 
 bool CChainState::FlushStateToDisk(const CChainParams &chainparams,
                                    BlockValidationState &state,
                                    FlushStateMode mode,
                                    int nManualPruneHeight) {
     LOCK(cs_main);
     assert(this->CanFlushToDisk());
     static std::chrono::microseconds nLastWrite{0};
     static std::chrono::microseconds nLastFlush{0};
     std::set<int> setFilesToPrune;
     bool full_flush_completed = false;
 
     const size_t coins_count = CoinsTip().GetCacheSize();
     const size_t coins_mem_usage = CoinsTip().DynamicMemoryUsage();
 
     try {
         {
             bool fFlushForPrune = false;
             bool fDoFullFlush = false;
             CoinsCacheSizeState cache_state =
                 GetCoinsCacheSizeState(&m_mempool);
             LOCK(cs_LastBlockFile);
             if (fPruneMode && (fCheckForPruning || nManualPruneHeight > 0) &&
                 !fReindex) {
                 if (nManualPruneHeight > 0) {
                     LOG_TIME_MILLIS_WITH_CATEGORY(
                         "find files to prune (manual)", BCLog::BENCH);
                     m_blockman.FindFilesToPruneManual(
                         setFilesToPrune, nManualPruneHeight, m_chain.Height());
                 } else {
                     LOG_TIME_MILLIS_WITH_CATEGORY("find files to prune",
                                                   BCLog::BENCH);
                     m_blockman.FindFilesToPrune(
                         setFilesToPrune, chainparams.PruneAfterHeight(),
                         m_chain.Height(), IsInitialBlockDownload());
                     fCheckForPruning = false;
                 }
                 if (!setFilesToPrune.empty()) {
                     fFlushForPrune = true;
                     if (!fHavePruned) {
                         pblocktree->WriteFlag("prunedblockfiles", true);
                         fHavePruned = true;
                     }
                 }
             }
             const auto nNow = GetTime<std::chrono::microseconds>();
             // Avoid writing/flushing immediately after startup.
             if (nLastWrite.count() == 0) {
                 nLastWrite = nNow;
             }
             if (nLastFlush.count() == 0) {
                 nLastFlush = nNow;
             }
             // The cache is large and we're within 10% and 10 MiB of the limit,
             // but we have time now (not in the middle of a block processing).
             bool fCacheLarge = mode == FlushStateMode::PERIODIC &&
                                cache_state >= CoinsCacheSizeState::LARGE;
             // The cache is over the limit, we have to write now.
             bool fCacheCritical = mode == FlushStateMode::IF_NEEDED &&
                                   cache_state >= CoinsCacheSizeState::CRITICAL;
             // It's been a while since we wrote the block index to disk. Do this
             // frequently, so we don't need to redownload after a crash.
             bool fPeriodicWrite = mode == FlushStateMode::PERIODIC &&
                                   nNow > nLastWrite + DATABASE_WRITE_INTERVAL;
             // It's been very long since we flushed the cache. Do this
             // infrequently, to optimize cache usage.
             bool fPeriodicFlush = mode == FlushStateMode::PERIODIC &&
                                   nNow > nLastFlush + DATABASE_FLUSH_INTERVAL;
             // Combine all conditions that result in a full cache flush.
             fDoFullFlush = (mode == FlushStateMode::ALWAYS) || fCacheLarge ||
                            fCacheCritical || fPeriodicFlush || fFlushForPrune;
             // Write blocks and block index to disk.
             if (fDoFullFlush || fPeriodicWrite) {
                 // Depend on nMinDiskSpace to ensure we can write block index
                 if (!CheckDiskSpace(GetBlocksDir())) {
                     return AbortNode(state, "Disk space is too low!",
                                      _("Disk space is too low!"));
                 }
 
                 {
                     LOG_TIME_MILLIS_WITH_CATEGORY(
                         "write block and undo data to disk", BCLog::BENCH);
 
                     // First make sure all block and undo data is flushed to
                     // disk.
                     FlushBlockFile();
                 }
                 // Then update all block file information (which may refer to
                 // block and undo files).
                 {
                     LOG_TIME_MILLIS_WITH_CATEGORY("write block index to disk",
                                                   BCLog::BENCH);
 
                     std::vector<std::pair<int, const CBlockFileInfo *>> vFiles;
                     vFiles.reserve(setDirtyFileInfo.size());
                     for (int i : setDirtyFileInfo) {
                         vFiles.push_back(std::make_pair(i, &vinfoBlockFile[i]));
                     }
 
                     setDirtyFileInfo.clear();
 
                     std::vector<const CBlockIndex *> vBlocks;
                     vBlocks.reserve(setDirtyBlockIndex.size());
                     for (const CBlockIndex *cbi : setDirtyBlockIndex) {
                         vBlocks.push_back(cbi);
                     }
 
                     setDirtyBlockIndex.clear();
 
                     if (!pblocktree->WriteBatchSync(vFiles, nLastBlockFile,
                                                     vBlocks)) {
                         return AbortNode(
                             state, "Failed to write to block index database");
                     }
                 }
 
                 // Finally remove any pruned files
                 if (fFlushForPrune) {
                     LOG_TIME_MILLIS_WITH_CATEGORY("unlink pruned files",
                                                   BCLog::BENCH);
 
                     UnlinkPrunedFiles(setFilesToPrune);
                 }
                 nLastWrite = nNow;
             }
             // Flush best chain related state. This can only be done if the
             // blocks / block index write was also done.
             if (fDoFullFlush && !CoinsTip().GetBestBlock().IsNull()) {
                 LOG_TIME_SECONDS(
                     strprintf("write coins cache to disk (%d coins, %.2fkB)",
                               coins_count, coins_mem_usage / 1000));
 
                 // Typical Coin structures on disk are around 48 bytes in size.
                 // Pushing a new one to the database can cause it to be written
                 // twice (once in the log, and once in the tables). This is
                 // already an overestimation, as most will delete an existing
                 // entry or overwrite one. Still, use a conservative safety
                 // factor of 2.
                 if (!CheckDiskSpace(GetDataDir(),
                                     48 * 2 * 2 * CoinsTip().GetCacheSize())) {
                     return AbortNode(state, "Disk space is too low!",
                                      _("Disk space is too low!"));
                 }
 
                 // Flush the chainstate (which may refer to block index
                 // entries).
                 if (!CoinsTip().Flush()) {
                     return AbortNode(state, "Failed to write to coin database");
                 }
                 nLastFlush = nNow;
                 full_flush_completed = true;
             }
         }
 
         if (full_flush_completed) {
             // Update best block in wallet (so we can detect restored wallets).
             GetMainSignals().ChainStateFlushed(m_chain.GetLocator());
         }
     } catch (const std::runtime_error &e) {
         return AbortNode(state, std::string("System error while flushing: ") +
                                     e.what());
     }
     return true;
 }
 
 void CChainState::ForceFlushStateToDisk() {
     BlockValidationState state;
     const CChainParams &chainparams = Params();
     if (!this->FlushStateToDisk(chainparams, state, FlushStateMode::ALWAYS)) {
         LogPrintf("%s: failed to flush state (%s)\n", __func__,
                   state.ToString());
     }
 }
 
 void CChainState::PruneAndFlush() {
     BlockValidationState state;
     fCheckForPruning = true;
     const CChainParams &chainparams = Params();
     if (!this->FlushStateToDisk(chainparams, state, FlushStateMode::NONE)) {
         LogPrintf("%s: failed to flush state (%s)\n", __func__,
                   state.ToString());
     }
 }
 
 /** Check warning conditions and do some notifications on new chain tip set. */
 static void UpdateTip(CTxMemPool &mempool, const CChainParams &params,
                       CBlockIndex *pindexNew)
     EXCLUSIVE_LOCKS_REQUIRED(::cs_main) {
     // New best block
     mempool.AddTransactionsUpdated(1);
 
     {
         LOCK(g_best_block_mutex);
         g_best_block = pindexNew->GetBlockHash();
         g_best_block_cv.notify_all();
     }
 
     LogPrintf("%s: new best=%s height=%d version=0x%08x log2_work=%f tx=%ld "
               "date='%s' progress=%f cache=%.1fMiB(%utxo)\n",
               __func__, pindexNew->GetBlockHash().ToString(),
               pindexNew->nHeight, pindexNew->nVersion,
               log(pindexNew->nChainWork.getdouble()) / log(2.0),
               pindexNew->GetChainTxCount(),
               FormatISO8601DateTime(pindexNew->GetBlockTime()),
               GuessVerificationProgress(params.TxData(), pindexNew),
               ::ChainstateActive().CoinsTip().DynamicMemoryUsage() *
                   (1.0 / (1 << 20)),
               ::ChainstateActive().CoinsTip().GetCacheSize());
 }
 
 /**
  * Disconnect m_chain's tip.
  * After calling, the mempool will be in an inconsistent state, with
  * transactions from disconnected blocks being added to disconnectpool. You
  * should make the mempool consistent again by calling updateMempoolForReorg.
  * with cs_main held.
  *
  * If disconnectpool is nullptr, then no disconnected transactions are added to
  * disconnectpool (note that the caller is responsible for mempool consistency
  * in any case).
  */
 bool CChainState::DisconnectTip(const CChainParams &params,
                                 BlockValidationState &state,
                                 DisconnectedBlockTransactions *disconnectpool) {
     AssertLockHeld(cs_main);
     AssertLockHeld(m_mempool.cs);
     CBlockIndex *pindexDelete = m_chain.Tip();
     const Consensus::Params &consensusParams = params.GetConsensus();
 
     assert(pindexDelete);
 
     // Read block from disk.
     std::shared_ptr<CBlock> pblock = std::make_shared<CBlock>();
     CBlock &block = *pblock;
     if (!ReadBlockFromDisk(block, pindexDelete, consensusParams)) {
         return error("DisconnectTip(): Failed to read block");
     }
 
     // Apply the block atomically to the chain state.
     int64_t nStart = GetTimeMicros();
     {
         CCoinsViewCache view(&CoinsTip());
         assert(view.GetBestBlock() == pindexDelete->GetBlockHash());
         if (DisconnectBlock(block, pindexDelete, view) !=
             DisconnectResult::OK) {
             return error("DisconnectTip(): DisconnectBlock %s failed",
                          pindexDelete->GetBlockHash().ToString());
         }
 
         bool flushed = view.Flush();
         assert(flushed);
     }
 
     LogPrint(BCLog::BENCH, "- Disconnect block: %.2fms\n",
              (GetTimeMicros() - nStart) * MILLI);
 
     // Write the chain state to disk, if necessary.
     if (!FlushStateToDisk(params, state, FlushStateMode::IF_NEEDED)) {
         return false;
     }
 
     // If this block is deactivating a fork, we move all mempool transactions
     // in front of disconnectpool for reprocessing in a future
     // updateMempoolForReorg call
     if (pindexDelete->pprev != nullptr &&
         GetNextBlockScriptFlags(consensusParams, pindexDelete) !=
             GetNextBlockScriptFlags(consensusParams, pindexDelete->pprev)) {
         LogPrint(BCLog::MEMPOOL,
                  "Disconnecting mempool due to rewind of upgrade block\n");
         if (disconnectpool) {
             disconnectpool->importMempool(m_mempool);
         }
         m_mempool.clear();
     }
 
     if (disconnectpool) {
         disconnectpool->addForBlock(block.vtx, m_mempool);
     }
 
     // If the tip is finalized, then undo it.
     if (m_finalizedBlockIndex == pindexDelete) {
         m_finalizedBlockIndex = pindexDelete->pprev;
     }
 
     m_chain.SetTip(pindexDelete->pprev);
 
     // Update ::ChainActive() and related variables.
     UpdateTip(m_mempool, params, pindexDelete->pprev);
     // Let wallets know transactions went from 1-confirmed to
     // 0-confirmed or conflicted:
     GetMainSignals().BlockDisconnected(pblock, pindexDelete);
     return true;
 }
 
 static int64_t nTimeReadFromDisk = 0;
 static int64_t nTimeConnectTotal = 0;
 static int64_t nTimeFlush = 0;
 static int64_t nTimeChainState = 0;
 static int64_t nTimePostConnect = 0;
 
 struct PerBlockConnectTrace {
     CBlockIndex *pindex = nullptr;
     std::shared_ptr<const CBlock> pblock;
     PerBlockConnectTrace() {}
 };
 
 /**
  * Used to track blocks whose transactions were applied to the UTXO state as a
  * part of a single ActivateBestChainStep call.
  *
  * This class is single-use, once you call GetBlocksConnected() you have to
  * throw it away and make a new one.
  */
 class ConnectTrace {
 private:
     std::vector<PerBlockConnectTrace> blocksConnected;
 
 public:
     explicit ConnectTrace() : blocksConnected(1) {}
 
     void BlockConnected(CBlockIndex *pindex,
                         std::shared_ptr<const CBlock> pblock) {
         assert(!blocksConnected.back().pindex);
         assert(pindex);
         assert(pblock);
         blocksConnected.back().pindex = pindex;
         blocksConnected.back().pblock = std::move(pblock);
         blocksConnected.emplace_back();
     }
 
     std::vector<PerBlockConnectTrace> &GetBlocksConnected() {
         // We always keep one extra block at the end of our list because blocks
         // are added after all the conflicted transactions have been filled in.
         // Thus, the last entry should always be an empty one waiting for the
         // transactions from the next block. We pop the last entry here to make
         // sure the list we return is sane.
         assert(!blocksConnected.back().pindex);
         blocksConnected.pop_back();
         return blocksConnected;
     }
 };
 
 bool CChainState::MarkBlockAsFinal(BlockValidationState &state,
                                    const CBlockIndex *pindex) {
     AssertLockHeld(cs_main);
     if (pindex->nStatus.isInvalid()) {
         // We try to finalize an invalid block.
         LogPrintf("ERROR: %s: Trying to finalize invalid block %s\n", __func__,
                   pindex->GetBlockHash().ToString());
         return state.Invalid(BlockValidationResult::BLOCK_CACHED_INVALID,
                              "finalize-invalid-block");
     }
 
     // Check that the request is consistent with current finalization.
     if (m_finalizedBlockIndex &&
         !AreOnTheSameFork(pindex, m_finalizedBlockIndex)) {
         LogPrintf("ERROR: %s: Trying to finalize block %s which conflicts with "
                   "already finalized block\n",
                   __func__, pindex->GetBlockHash().ToString());
         return state.Invalid(BlockValidationResult::BLOCK_FINALIZATION,
                              "bad-fork-prior-finalized");
     }
 
     if (IsBlockFinalized(pindex)) {
         // The block is already finalized.
         return true;
     }
 
     // We have a new block to finalize.
     m_finalizedBlockIndex = pindex;
     return true;
 }
 
 static const CBlockIndex *FindBlockToFinalize(CBlockIndex *pindexNew)
     EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
     AssertLockHeld(cs_main);
 
     const int32_t maxreorgdepth =
         gArgs.GetArg("-maxreorgdepth", DEFAULT_MAX_REORG_DEPTH);
 
     const int64_t finalizationdelay =
         gArgs.GetArg("-finalizationdelay", DEFAULT_MIN_FINALIZATION_DELAY);
 
     // Find our candidate.
     // If maxreorgdepth is < 0 pindex will be null and auto finalization
     // disabled
     const CBlockIndex *pindex =
         pindexNew->GetAncestor(pindexNew->nHeight - maxreorgdepth);
 
     int64_t now = GetTime();
 
     // If the finalization delay is not expired since the startup time,
     // finalization should be avoided. Header receive time is not saved to disk
     // and so cannot be anterior to startup time.
     if (now < (GetStartupTime() + finalizationdelay)) {
         return nullptr;
     }
 
     // While our candidate is not eligible (finalization delay not expired), try
     // the previous one.
     while (pindex && (pindex != ::ChainstateActive().GetFinalizedBlock())) {
         // Check that the block to finalize is known for a long enough time.
         // This test will ensure that an attacker could not cause a block to
         // finalize by forking the chain with a depth > maxreorgdepth.
         // If the block is loaded from disk, header receive time is 0 and the
         // block will be finalized. This is safe because the delay since the
         // node startup is already expired.
         auto headerReceivedTime = pindex->GetHeaderReceivedTime();
 
         // If finalization delay is <= 0, finalization always occurs immediately
         if (now >= (headerReceivedTime + finalizationdelay)) {
             return pindex;
         }
 
         pindex = pindex->pprev;
     }
 
     return nullptr;
 }
 
 /**
  * Connect a new block to m_chain. pblock is either nullptr or a pointer to
  * a CBlock corresponding to pindexNew, to bypass loading it again from disk.
  *
  * The block is always added to connectTrace (either after loading from disk or
  * by copying pblock) - if that is not intended, care must be taken to remove
  * the last entry in blocksConnected in case of failure.
  */
 bool CChainState::ConnectTip(const Config &config, BlockValidationState &state,
                              CBlockIndex *pindexNew,
                              const std::shared_ptr<const CBlock> &pblock,
                              ConnectTrace &connectTrace,
                              DisconnectedBlockTransactions &disconnectpool) {
     AssertLockHeld(cs_main);
     AssertLockHeld(m_mempool.cs);
 
     const CChainParams &params = config.GetChainParams();
     const Consensus::Params &consensusParams = params.GetConsensus();
 
     assert(pindexNew->pprev == m_chain.Tip());
     // Read block from disk.
     int64_t nTime1 = GetTimeMicros();
     std::shared_ptr<const CBlock> pthisBlock;
     if (!pblock) {
         std::shared_ptr<CBlock> pblockNew = std::make_shared<CBlock>();
         if (!ReadBlockFromDisk(*pblockNew, pindexNew, consensusParams)) {
             return AbortNode(state, "Failed to read block");
         }
         pthisBlock = pblockNew;
     } else {
         pthisBlock = pblock;
     }
 
     const CBlock &blockConnecting = *pthisBlock;
 
     // Apply the block atomically to the chain state.
     int64_t nTime2 = GetTimeMicros();
     nTimeReadFromDisk += nTime2 - nTime1;
     int64_t nTime3;
     LogPrint(BCLog::BENCH, "  - Load block from disk: %.2fms [%.2fs]\n",
              (nTime2 - nTime1) * MILLI, nTimeReadFromDisk * MICRO);
     {
         CCoinsViewCache view(&CoinsTip());
         bool rv = ConnectBlock(blockConnecting, state, pindexNew, view, params,
                                BlockValidationOptions(config));
         GetMainSignals().BlockChecked(blockConnecting, state);
         if (!rv) {
             if (state.IsInvalid()) {
                 InvalidBlockFound(pindexNew, state);
             }
 
             return error("%s: ConnectBlock %s failed, %s", __func__,
                          pindexNew->GetBlockHash().ToString(),
                          state.ToString());
         }
 
         // Update the finalized block.
         const CBlockIndex *pindexToFinalize = FindBlockToFinalize(pindexNew);
         if (pindexToFinalize && !MarkBlockAsFinal(state, pindexToFinalize)) {
             return error("ConnectTip(): MarkBlockAsFinal %s failed (%s)",
                          pindexNew->GetBlockHash().ToString(),
                          state.ToString());
         }
 
         nTime3 = GetTimeMicros();
         nTimeConnectTotal += nTime3 - nTime2;
         assert(nBlocksTotal > 0);
         LogPrint(BCLog::BENCH,
                  "  - Connect total: %.2fms [%.2fs (%.2fms/blk)]\n",
                  (nTime3 - nTime2) * MILLI, nTimeConnectTotal * MICRO,
                  nTimeConnectTotal * MILLI / nBlocksTotal);
         bool flushed = view.Flush();
         assert(flushed);
     }
 
     int64_t nTime4 = GetTimeMicros();
     nTimeFlush += nTime4 - nTime3;
     LogPrint(BCLog::BENCH, "  - Flush: %.2fms [%.2fs (%.2fms/blk)]\n",
              (nTime4 - nTime3) * MILLI, nTimeFlush * MICRO,
              nTimeFlush * MILLI / nBlocksTotal);
 
     // Write the chain state to disk, if necessary.
     if (!FlushStateToDisk(config.GetChainParams(), state,
                           FlushStateMode::IF_NEEDED)) {
         return false;
     }
 
     int64_t nTime5 = GetTimeMicros();
     nTimeChainState += nTime5 - nTime4;
     LogPrint(BCLog::BENCH,
              "  - Writing chainstate: %.2fms [%.2fs (%.2fms/blk)]\n",
              (nTime5 - nTime4) * MILLI, nTimeChainState * MICRO,
              nTimeChainState * MILLI / nBlocksTotal);
 
     // Remove conflicting transactions from the mempool.;
     m_mempool.removeForBlock(blockConnecting.vtx, pindexNew->nHeight);
     disconnectpool.removeForBlock(blockConnecting.vtx);
 
     // If this block is activating a fork, we move all mempool transactions
     // in front of disconnectpool for reprocessing in a future
     // updateMempoolForReorg call
     if (pindexNew->pprev != nullptr &&
         GetNextBlockScriptFlags(consensusParams, pindexNew) !=
             GetNextBlockScriptFlags(consensusParams, pindexNew->pprev)) {
         LogPrint(BCLog::MEMPOOL,
                  "Disconnecting mempool due to acceptance of upgrade block\n");
         disconnectpool.importMempool(m_mempool);
     }
 
     // Update m_chain & related variables.
     m_chain.SetTip(pindexNew);
     UpdateTip(m_mempool, params, pindexNew);
 
     int64_t nTime6 = GetTimeMicros();
     nTimePostConnect += nTime6 - nTime5;
     nTimeTotal += nTime6 - nTime1;
     LogPrint(BCLog::BENCH,
              "  - Connect postprocess: %.2fms [%.2fs (%.2fms/blk)]\n",
              (nTime6 - nTime5) * MILLI, nTimePostConnect * MICRO,
              nTimePostConnect * MILLI / nBlocksTotal);
     LogPrint(BCLog::BENCH, "- Connect block: %.2fms [%.2fs (%.2fms/blk)]\n",
              (nTime6 - nTime1) * MILLI, nTimeTotal * MICRO,
              nTimeTotal * MILLI / nBlocksTotal);
 
     connectTrace.BlockConnected(pindexNew, std::move(pthisBlock));
     return true;
 }
 
 /**
  * Return the tip of the chain with the most work in it, that isn't known to be
  * invalid (it's however far from certain to be valid).
  */
 CBlockIndex *CChainState::FindMostWorkChain() {
     AssertLockHeld(cs_main);
     do {
         CBlockIndex *pindexNew = nullptr;
 
         // Find the best candidate header.
         {
             std::set<CBlockIndex *, CBlockIndexWorkComparator>::reverse_iterator
                 it = setBlockIndexCandidates.rbegin();
             if (it == setBlockIndexCandidates.rend()) {
                 return nullptr;
             }
             pindexNew = *it;
         }
 
         // If this block will cause a finalized block to be reorged, then we
         // mark it as invalid.
         if (m_finalizedBlockIndex &&
             !AreOnTheSameFork(pindexNew, m_finalizedBlockIndex)) {
             LogPrintf("Mark block %s invalid because it forks prior to the "
                       "finalization point %d.\n",
                       pindexNew->GetBlockHash().ToString(),
                       m_finalizedBlockIndex->nHeight);
             pindexNew->nStatus = pindexNew->nStatus.withFailed();
             InvalidChainFound(pindexNew);
         }
 
         const bool fAvalancheEnabled = isAvalancheEnabled(gArgs);
         const bool fAutoUnpark =
             gArgs.GetBoolArg("-automaticunparking", !fAvalancheEnabled);
 
         const CBlockIndex *pindexFork = m_chain.FindFork(pindexNew);
 
         // Check whether all blocks on the path between the currently active
         // chain and the candidate are valid. Just going until the active chain
         // is an optimization, as we know all blocks in it are valid already.
         CBlockIndex *pindexTest = pindexNew;
         bool hasValidAncestor = true;
         while (hasValidAncestor && pindexTest && pindexTest != pindexFork) {
             assert(pindexTest->HaveTxsDownloaded() || pindexTest->nHeight == 0);
 
             // If this is a parked chain, but it has enough PoW, clear the park
             // state.
             bool fParkedChain = pindexTest->nStatus.isOnParkedChain();
             if (fAutoUnpark && fParkedChain) {
                 const CBlockIndex *pindexTip = m_chain.Tip();
 
                 // During initialization, pindexTip and/or pindexFork may be
                 // null. In this case, we just ignore the fact that the chain is
                 // parked.
                 if (!pindexTip || !pindexFork) {
                     UnparkBlock(pindexTest);
                     continue;
                 }
 
                 // A parked chain can be unparked if it has twice as much PoW
                 // accumulated as the main chain has since the fork block.
                 CBlockIndex const *pindexExtraPow = pindexTip;
                 arith_uint256 requiredWork = pindexTip->nChainWork;
                 switch (pindexTip->nHeight - pindexFork->nHeight) {
                     // Limit the penality for depth 1, 2 and 3 to half a block
                     // worth of work to ensure we don't fork accidentally.
                     case 3:
                     case 2:
                         pindexExtraPow = pindexExtraPow->pprev;
                     // FALLTHROUGH
                     case 1: {
                         const arith_uint256 deltaWork =
                             pindexExtraPow->nChainWork - pindexFork->nChainWork;
                         requiredWork += (deltaWork >> 1);
                         break;
                     }
                     default:
                         requiredWork +=
                             pindexExtraPow->nChainWork - pindexFork->nChainWork;
                         break;
                 }
 
                 if (pindexNew->nChainWork > requiredWork) {
                     // We have enough, clear the parked state.
                     LogPrintf("Unpark chain up to block %s as it has "
                               "accumulated enough PoW.\n",
                               pindexNew->GetBlockHash().ToString());
                     fParkedChain = false;
                     UnparkBlock(pindexTest);
                 }
             }
 
             // Pruned nodes may have entries in setBlockIndexCandidates for
             // which block files have been deleted. Remove those as candidates
             // for the most work chain if we come across them; we can't switch
             // to a chain unless we have all the non-active-chain parent blocks.
             bool fInvalidChain = pindexTest->nStatus.isInvalid();
             bool fMissingData = !pindexTest->nStatus.hasData();
             if (!(fInvalidChain || fParkedChain || fMissingData)) {
                 // The current block is acceptable, move to the parent, up to
                 // the fork point.
                 pindexTest = pindexTest->pprev;
                 continue;
             }
 
             // Candidate chain is not usable (either invalid or parked or
             // missing data)
             hasValidAncestor = false;
             setBlockIndexCandidates.erase(pindexTest);
 
             if (fInvalidChain &&
                 (pindexBestInvalid == nullptr ||
                  pindexNew->nChainWork > pindexBestInvalid->nChainWork)) {
                 pindexBestInvalid = pindexNew;
             }
 
             if (fParkedChain &&
                 (pindexBestParked == nullptr ||
                  pindexNew->nChainWork > pindexBestParked->nChainWork)) {
                 pindexBestParked = pindexNew;
             }
 
             LogPrintf("Considered switching to better tip %s but that chain "
                       "contains a%s%s%s block.\n",
                       pindexNew->GetBlockHash().ToString(),
                       fInvalidChain ? "n invalid" : "",
                       fParkedChain ? " parked" : "",
                       fMissingData ? " missing-data" : "");
 
             CBlockIndex *pindexFailed = pindexNew;
             // Remove the entire chain from the set.
             while (pindexTest != pindexFailed) {
                 if (fInvalidChain || fParkedChain) {
                     pindexFailed->nStatus =
                         pindexFailed->nStatus.withFailedParent(fInvalidChain)
                             .withParkedParent(fParkedChain);
                 } else if (fMissingData) {
                     // If we're missing data, then add back to
                     // m_blocks_unlinked, so that if the block arrives in the
                     // future we can try adding to setBlockIndexCandidates
                     // again.
                     m_blockman.m_blocks_unlinked.insert(
                         std::make_pair(pindexFailed->pprev, pindexFailed));
                 }
                 setBlockIndexCandidates.erase(pindexFailed);
                 pindexFailed = pindexFailed->pprev;
             }
 
             if (fInvalidChain || fParkedChain) {
                 // We discovered a new chain tip that is either parked or
                 // invalid, we may want to warn.
                 CheckForkWarningConditionsOnNewFork(pindexNew);
             }
         }
 
         if (fAvalancheEnabled && g_avalanche) {
             g_avalanche->addBlockToReconcile(pindexNew);
         }
 
         // We found a candidate that has valid ancestors. This is our guy.
         if (hasValidAncestor) {
             return pindexNew;
         }
     } while (true);
 }
 
 /**
  * Delete all entries in setBlockIndexCandidates that are worse than the current
  * tip.
  */
 void CChainState::PruneBlockIndexCandidates() {
     // Note that we can't delete the current block itself, as we may need to
     // return to it later in case a reorganization to a better block fails.
     auto it = setBlockIndexCandidates.begin();
     while (it != setBlockIndexCandidates.end() &&
            setBlockIndexCandidates.value_comp()(*it, m_chain.Tip())) {
         setBlockIndexCandidates.erase(it++);
     }
 
     // Either the current tip or a successor of it we're working towards is left
     // in setBlockIndexCandidates.
     assert(!setBlockIndexCandidates.empty());
 }
 
 /**
  * Try to make some progress towards making pindexMostWork the active block.
  * pblock is either nullptr or a pointer to a CBlock corresponding to
  * pindexMostWork.
  *
  * @returns true unless a system error occurred
  */
 bool CChainState::ActivateBestChainStep(
     const Config &config, BlockValidationState &state,
     CBlockIndex *pindexMostWork, const std::shared_ptr<const CBlock> &pblock,
     bool &fInvalidFound, ConnectTrace &connectTrace) {
     AssertLockHeld(cs_main);
     AssertLockHeld(m_mempool.cs);
 
     const CBlockIndex *pindexOldTip = m_chain.Tip();
     const CBlockIndex *pindexFork = m_chain.FindFork(pindexMostWork);
 
     // Disconnect active blocks which are no longer in the best chain.
     bool fBlocksDisconnected = false;
     DisconnectedBlockTransactions disconnectpool;
     while (m_chain.Tip() && m_chain.Tip() != pindexFork) {
         if (!DisconnectTip(config.GetChainParams(), state, &disconnectpool)) {
             // This is likely a fatal error, but keep the mempool consistent,
             // just in case. Only remove from the mempool in this case.
             disconnectpool.updateMempoolForReorg(config, false, m_mempool);
 
             // If we're unable to disconnect a block during normal operation,
             // then that is a failure of our local system -- we should abort
             // rather than stay on a less work chain.
             AbortNode(state,
                       "Failed to disconnect block; see debug.log for details");
             return false;
         }
 
         fBlocksDisconnected = true;
     }
 
     // Build list of new blocks to connect.
     std::vector<CBlockIndex *> vpindexToConnect;
     bool fContinue = true;
     int nHeight = pindexFork ? pindexFork->nHeight : -1;
     while (fContinue && nHeight != pindexMostWork->nHeight) {
         // Don't iterate the entire list of potential improvements toward the
         // best tip, as we likely only need a few blocks along the way.
         int nTargetHeight = std::min(nHeight + 32, pindexMostWork->nHeight);
         vpindexToConnect.clear();
         vpindexToConnect.reserve(nTargetHeight - nHeight);
         CBlockIndex *pindexIter = pindexMostWork->GetAncestor(nTargetHeight);
         while (pindexIter && pindexIter->nHeight != nHeight) {
             vpindexToConnect.push_back(pindexIter);
             pindexIter = pindexIter->pprev;
         }
 
         nHeight = nTargetHeight;
 
         // Connect new blocks.
         for (CBlockIndex *pindexConnect : reverse_iterate(vpindexToConnect)) {
             if (!ConnectTip(config, state, pindexConnect,
                             pindexConnect == pindexMostWork
                                 ? pblock
                                 : std::shared_ptr<const CBlock>(),
                             connectTrace, disconnectpool)) {
                 if (state.IsInvalid()) {
                     // The block violates a consensus rule.
                     if (state.GetResult() !=
                         BlockValidationResult::BLOCK_MUTATED) {
                         InvalidChainFound(vpindexToConnect.back());
                     }
                     state = BlockValidationState();
                     fInvalidFound = true;
                     fContinue = false;
                     break;
                 }
 
                 // A system error occurred (disk space, database error, ...).
                 // Make the mempool consistent with the current tip, just in
                 // case any observers try to use it before shutdown.
                 disconnectpool.updateMempoolForReorg(config, false, m_mempool);
                 return false;
             } else {
                 PruneBlockIndexCandidates();
                 if (!pindexOldTip ||
                     m_chain.Tip()->nChainWork > pindexOldTip->nChainWork) {
                     // We're in a better position than we were. Return
                     // temporarily to release the lock.
                     fContinue = false;
                     break;
                 }
             }
         }
     }
 
     if (fBlocksDisconnected || !disconnectpool.isEmpty()) {
         // If any blocks were disconnected, we need to update the mempool even
         // if disconnectpool is empty. The disconnectpool may also be non-empty
         // if the mempool was imported due to new validation rules being in
         // effect.
         LogPrint(BCLog::MEMPOOL, "Updating mempool due to reorganization or "
                                  "rules upgrade/downgrade\n");
         disconnectpool.updateMempoolForReorg(config, true, m_mempool);
     }
 
     m_mempool.check(&CoinsTip());
 
     // Callbacks/notifications for a new best chain.
     if (fInvalidFound) {
         CheckForkWarningConditionsOnNewFork(pindexMostWork);
     } else {
         CheckForkWarningConditions();
     }
 
     return true;
 }
 
 static SynchronizationState GetSynchronizationState(bool init) {
     if (!init) {
         return SynchronizationState::POST_INIT;
     }
     if (::fReindex) {
         return SynchronizationState::INIT_REINDEX;
     }
     return SynchronizationState::INIT_DOWNLOAD;
 }
 
 static bool NotifyHeaderTip() LOCKS_EXCLUDED(cs_main) {
     bool fNotify = false;
     bool fInitialBlockDownload = false;
     static CBlockIndex *pindexHeaderOld = nullptr;
     CBlockIndex *pindexHeader = nullptr;
     {
         LOCK(cs_main);
         pindexHeader = pindexBestHeader;
 
         if (pindexHeader != pindexHeaderOld) {
             fNotify = true;
             fInitialBlockDownload =
                 ::ChainstateActive().IsInitialBlockDownload();
             pindexHeaderOld = pindexHeader;
         }
     }
 
     // Send block tip changed notifications without cs_main
     if (fNotify) {
         uiInterface.NotifyHeaderTip(
             GetSynchronizationState(fInitialBlockDownload), pindexHeader);
     }
     return fNotify;
 }
 
 static void LimitValidationInterfaceQueue() LOCKS_EXCLUDED(cs_main) {
     AssertLockNotHeld(cs_main);
 
     if (GetMainSignals().CallbacksPending() > 10) {
         SyncWithValidationInterfaceQueue();
     }
 }
 
 bool CChainState::ActivateBestChain(const Config &config,
                                     BlockValidationState &state,
                                     std::shared_ptr<const CBlock> pblock) {
     // Note that while we're often called here from ProcessNewBlock, this is
     // far from a guarantee. Things in the P2P/RPC will often end up calling
     // us in the middle of ProcessNewBlock - do not assume pblock is set
     // sanely for performance or correctness!
     AssertLockNotHeld(cs_main);
 
     const CChainParams &params = config.GetChainParams();
 
     // ABC maintains a fair degree of expensive-to-calculate internal state
     // because this function periodically releases cs_main so that it does not
     // lock up other threads for too long during large connects - and to allow
     // for e.g. the callback queue to drain we use m_cs_chainstate to enforce
     // mutual exclusion so that only one caller may execute this function at a
     // time
     LOCK(m_cs_chainstate);
 
     CBlockIndex *pindexMostWork = nullptr;
     CBlockIndex *pindexNewTip = nullptr;
     int nStopAtHeight = gArgs.GetArg("-stopatheight", DEFAULT_STOPATHEIGHT);
     do {
         // Block until the validation queue drains. This should largely
         // never happen in normal operation, however may happen during
         // reindex, causing memory blowup if we run too far ahead.
         // Note that if a validationinterface callback ends up calling
         // ActivateBestChain this may lead to a deadlock! We should
         // probably have a DEBUG_LOCKORDER test for this in the future.
         LimitValidationInterfaceQueue();
 
         {
             LOCK(cs_main);
             // Lock transaction pool for at least as long as it takes for
             // connectTrace to be consumed
             LOCK(m_mempool.cs);
             CBlockIndex *starting_tip = m_chain.Tip();
             bool blocks_connected = false;
             do {
                 // We absolutely may not unlock cs_main until we've made forward
                 // progress (with the exception of shutdown due to hardware
                 // issues, low disk space, etc).
 
                 // Destructed before cs_main is unlocked
                 ConnectTrace connectTrace;
 
                 if (pindexMostWork == nullptr) {
                     pindexMostWork = FindMostWorkChain();
                 }
 
                 // Whether we have anything to do at all.
                 if (pindexMostWork == nullptr ||
                     pindexMostWork == m_chain.Tip()) {
                     break;
                 }
 
                 bool fInvalidFound = false;
                 std::shared_ptr<const CBlock> nullBlockPtr;
                 if (!ActivateBestChainStep(
                         config, state, pindexMostWork,
                         pblock && pblock->GetHash() ==
                                       pindexMostWork->GetBlockHash()
                             ? pblock
                             : nullBlockPtr,
                         fInvalidFound, connectTrace)) {
                     // A system error occurred
                     return false;
                 }
                 blocks_connected = true;
 
                 if (fInvalidFound) {
                     // Wipe cache, we may need another branch now.
                     pindexMostWork = nullptr;
                 }
 
                 pindexNewTip = m_chain.Tip();
                 for (const PerBlockConnectTrace &trace :
                      connectTrace.GetBlocksConnected()) {
                     assert(trace.pblock && trace.pindex);
                     GetMainSignals().BlockConnected(trace.pblock, trace.pindex);
                 }
             } while (!m_chain.Tip() ||
                      (starting_tip && CBlockIndexWorkComparator()(
                                           m_chain.Tip(), starting_tip)));
 
             // Check the index once we're done with the above loop, since
             // we're going to release cs_main soon. If the index is in a bad
             // state now, then it's better to know immediately rather than
             // randomly have it cause a problem in a race.
             CheckBlockIndex(params.GetConsensus());
 
             if (!blocks_connected) {
                 return true;
             }
 
             const CBlockIndex *pindexFork = m_chain.FindFork(starting_tip);
             bool fInitialDownload = IsInitialBlockDownload();
 
             // Notify external listeners about the new tip.
             // Enqueue while holding cs_main to ensure that UpdatedBlockTip is
             // called in the order in which blocks are connected
             if (pindexFork != pindexNewTip) {
                 // Notify ValidationInterface subscribers
                 GetMainSignals().UpdatedBlockTip(pindexNewTip, pindexFork,
                                                  fInitialDownload);
 
                 // Always notify the UI if a new block tip was connected
                 uiInterface.NotifyBlockTip(
                     GetSynchronizationState(fInitialDownload), pindexNewTip);
             }
         }
         // When we reach this point, we switched to a new tip (stored in
         // pindexNewTip).
 
         if (nStopAtHeight && pindexNewTip &&
             pindexNewTip->nHeight >= nStopAtHeight) {
             StartShutdown();
         }
 
         // We check shutdown only after giving ActivateBestChainStep a chance to
         // run once so that we never shutdown before connecting the genesis
         // block during LoadChainTip(). Previously this caused an assert()
         // failure during shutdown in such cases as the UTXO DB flushing checks
         // that the best block hash is non-null.
         if (ShutdownRequested()) {
             break;
         }
     } while (pindexNewTip != pindexMostWork);
 
     // Write changes periodically to disk, after relay.
     if (!FlushStateToDisk(params, state, FlushStateMode::PERIODIC)) {
         return false;
     }
 
     return true;
 }
 
 bool ActivateBestChain(const Config &config, BlockValidationState &state,
                        std::shared_ptr<const CBlock> pblock) {
     return ::ChainstateActive().ActivateBestChain(config, state,
                                                   std::move(pblock));
 }
 
 bool CChainState::PreciousBlock(const Config &config,
                                 BlockValidationState &state,
                                 CBlockIndex *pindex) {
     {
         LOCK(cs_main);
         if (pindex->nChainWork < m_chain.Tip()->nChainWork) {
             // Nothing to do, this block is not at the tip.
             return true;
         }
 
         if (m_chain.Tip()->nChainWork > nLastPreciousChainwork) {
             // The chain has been extended since the last call, reset the
             // counter.
             nBlockReverseSequenceId = -1;
         }
 
         nLastPreciousChainwork = m_chain.Tip()->nChainWork;
         setBlockIndexCandidates.erase(pindex);
         pindex->nSequenceId = nBlockReverseSequenceId;
         if (nBlockReverseSequenceId > std::numeric_limits<int32_t>::min()) {
             // We can't keep reducing the counter if somebody really wants to
             // call preciousblock 2**31-1 times on the same set of tips...
             nBlockReverseSequenceId--;
         }
 
         // In case this was parked, unpark it.
         UnparkBlock(pindex);
 
         // Make sure it is added to the candidate list if appropriate.
         if (pindex->IsValid(BlockValidity::TRANSACTIONS) &&
             pindex->HaveTxsDownloaded()) {
             setBlockIndexCandidates.insert(pindex);
             PruneBlockIndexCandidates();
         }
     }
 
     return ActivateBestChain(config, state);
 }
 
 bool PreciousBlock(const Config &config, BlockValidationState &state,
                    CBlockIndex *pindex) {
     return ::ChainstateActive().PreciousBlock(config, state, pindex);
 }
 
 bool CChainState::UnwindBlock(const Config &config, BlockValidationState &state,
                               CBlockIndex *pindex, bool invalidate) {
     CBlockIndex *to_mark_failed_or_parked = pindex;
     bool pindex_was_in_chain = false;
     int disconnected = 0;
     const CChainParams &chainparams = config.GetChainParams();
 
     // We do not allow ActivateBestChain() to run while UnwindBlock() is
     // running, as that could cause the tip to change while we disconnect
     // blocks. (Note for backport of Core PR16849: we acquire
     // LOCK(m_cs_chainstate) in the Park, Invalidate and FinalizeBlock functions
     // due to differences in our code)
     AssertLockHeld(m_cs_chainstate);
 
     // We'll be acquiring and releasing cs_main below, to allow the validation
     // callbacks to run. However, we should keep the block index in a
     // consistent state as we disconnect blocks -- in particular we need to
     // add equal-work blocks to setBlockIndexCandidates as we disconnect.
     // To avoid walking the block index repeatedly in search of candidates,
     // build a map once so that we can look up candidate blocks by chain
     // work as we go.
     std::multimap<const arith_uint256, CBlockIndex *> candidate_blocks_by_work;
 
     {
         LOCK(cs_main);
         for (const auto &entry : m_blockman.m_block_index) {
             CBlockIndex *candidate = entry.second;
             // We don't need to put anything in our active chain into the
             // multimap, because those candidates will be found and considered
             // as we disconnect.
             // Instead, consider only non-active-chain blocks that have at
             // least as much work as where we expect the new tip to end up.
             if (!m_chain.Contains(candidate) &&
                 !CBlockIndexWorkComparator()(candidate, pindex->pprev) &&
                 candidate->IsValid(BlockValidity::TRANSACTIONS) &&
                 candidate->HaveTxsDownloaded()) {
                 candidate_blocks_by_work.insert(
                     std::make_pair(candidate->nChainWork, candidate));
             }
         }
     }
 
     // Disconnect (descendants of) pindex, and mark them invalid.
     while (true) {
         if (ShutdownRequested()) {
             break;
         }
 
         // Make sure the queue of validation callbacks doesn't grow unboundedly.
         LimitValidationInterfaceQueue();
 
         LOCK(cs_main);
         // Lock for as long as disconnectpool is in scope to make sure
         // UpdateMempoolForReorg is called after DisconnectTip without unlocking
         // in between
         LOCK(m_mempool.cs);
 
         if (!m_chain.Contains(pindex)) {
             break;
         }
 
         pindex_was_in_chain = true;
         CBlockIndex *invalid_walk_tip = m_chain.Tip();
 
         // ActivateBestChain considers blocks already in m_chain
         // unconditionally valid already, so force disconnect away from it.
 
         DisconnectedBlockTransactions disconnectpool;
 
         bool ret = DisconnectTip(chainparams, state, &disconnectpool);
 
         // DisconnectTip will add transactions to disconnectpool.
         // Adjust the mempool to be consistent with the new tip, adding
         // transactions back to the mempool if disconnecting was successful,
         // and we're not doing a very deep invalidation (in which case
         // keeping the mempool up to date is probably futile anyway).
         disconnectpool.updateMempoolForReorg(
             config, /* fAddToMempool = */ (++disconnected <= 10) && ret,
             m_mempool);
 
         if (!ret) {
             return false;
         }
 
         assert(invalid_walk_tip->pprev == m_chain.Tip());
 
         // We immediately mark the disconnected blocks as invalid.
         // This prevents a case where pruned nodes may fail to invalidateblock
         // and be left unable to start as they have no tip candidates (as there
         // are no blocks that meet the "have data and are not invalid per
         // nStatus" criteria for inclusion in setBlockIndexCandidates).
 
         invalid_walk_tip->nStatus =
             invalidate ? invalid_walk_tip->nStatus.withFailed()
                        : invalid_walk_tip->nStatus.withParked();
 
         setDirtyBlockIndex.insert(invalid_walk_tip);
         setBlockIndexCandidates.insert(invalid_walk_tip->pprev);
 
         if (invalid_walk_tip == to_mark_failed_or_parked->pprev &&
             (invalidate ? to_mark_failed_or_parked->nStatus.hasFailed()
                         : to_mark_failed_or_parked->nStatus.isParked())) {
             // We only want to mark the last disconnected block as
             // Failed (or Parked); its children need to be FailedParent (or
             // ParkedParent) instead.
             to_mark_failed_or_parked->nStatus =
                 (invalidate
                      ? to_mark_failed_or_parked->nStatus.withFailed(false)
                            .withFailedParent()
                      : to_mark_failed_or_parked->nStatus.withParked(false)
                            .withParkedParent());
 
             setDirtyBlockIndex.insert(to_mark_failed_or_parked);
         }
 
         // Add any equal or more work headers to setBlockIndexCandidates
         auto candidate_it = candidate_blocks_by_work.lower_bound(
             invalid_walk_tip->pprev->nChainWork);
         while (candidate_it != candidate_blocks_by_work.end()) {
             if (!CBlockIndexWorkComparator()(candidate_it->second,
                                              invalid_walk_tip->pprev)) {
                 setBlockIndexCandidates.insert(candidate_it->second);
                 candidate_it = candidate_blocks_by_work.erase(candidate_it);
             } else {
                 ++candidate_it;
             }
         }
 
         // Track the last disconnected block, so we can correct its
         // FailedParent (or ParkedParent) status in future iterations, or, if
         // it's the last one, call InvalidChainFound on it.
         to_mark_failed_or_parked = invalid_walk_tip;
     }
 
     CheckBlockIndex(chainparams.GetConsensus());
 
     {
         LOCK(cs_main);
         if (m_chain.Contains(to_mark_failed_or_parked)) {
             // If the to-be-marked invalid block is in the active chain,
             // something is interfering and we can't proceed.
             return false;
         }
 
         // Mark pindex (or the last disconnected block) as invalid (or parked),
         // even when it never was in the main chain.
         to_mark_failed_or_parked->nStatus =
             invalidate ? to_mark_failed_or_parked->nStatus.withFailed()
                        : to_mark_failed_or_parked->nStatus.withParked();
         setDirtyBlockIndex.insert(to_mark_failed_or_parked);
         if (invalidate) {
             m_blockman.m_failed_blocks.insert(to_mark_failed_or_parked);
         }
 
         // If any new blocks somehow arrived while we were disconnecting
         // (above), then the pre-calculation of what should go into
         // setBlockIndexCandidates may have missed entries. This would
         // technically be an inconsistency in the block index, but if we clean
         // it up here, this should be an essentially unobservable error.
         // Loop back over all block index entries and add any missing entries
         // to setBlockIndexCandidates.
         for (const std::pair<const BlockHash, CBlockIndex *> &it :
              m_blockman.m_block_index) {
             CBlockIndex *i = it.second;
             if (i->IsValid(BlockValidity::TRANSACTIONS) &&
                 i->HaveTxsDownloaded() &&
                 !setBlockIndexCandidates.value_comp()(i, m_chain.Tip())) {
                 setBlockIndexCandidates.insert(i);
             }
         }
 
         if (invalidate) {
             InvalidChainFound(to_mark_failed_or_parked);
         }
     }
 
     // Only notify about a new block tip if the active chain was modified.
     if (pindex_was_in_chain) {
         uiInterface.NotifyBlockTip(
             GetSynchronizationState(IsInitialBlockDownload()),
             to_mark_failed_or_parked->pprev);
     }
     return true;
 }
 
 bool CChainState::InvalidateBlock(const Config &config,
                                   BlockValidationState &state,
                                   CBlockIndex *pindex) {
     AssertLockNotHeld(m_cs_chainstate);
     // See 'Note for backport of Core PR16849' in CChainState::UnwindBlock
     LOCK(m_cs_chainstate);
 
     return UnwindBlock(config, state, pindex, true);
 }
 
 bool CChainState::ParkBlock(const Config &config, BlockValidationState &state,
                             CBlockIndex *pindex) {
     AssertLockNotHeld(m_cs_chainstate);
     // See 'Note for backport of Core PR16849' in CChainState::UnwindBlock
     LOCK(m_cs_chainstate);
 
     return UnwindBlock(config, state, pindex, false);
 }
 
 bool CChainState::FinalizeBlock(const Config &config,
                                 BlockValidationState &state,
                                 CBlockIndex *pindex) {
     AssertLockNotHeld(m_cs_chainstate);
     // See 'Note for backport of Core PR16849' in CChainState::UnwindBlock
     LOCK(m_cs_chainstate);
 
     AssertLockNotHeld(cs_main);
     CBlockIndex *pindexToInvalidate = nullptr;
     {
         LOCK(cs_main);
         if (!MarkBlockAsFinal(state, pindex)) {
             // state is set by MarkBlockAsFinal.
             return false;
         }
 
         // We have a valid candidate, make sure it is not parked.
         if (pindex->nStatus.isOnParkedChain()) {
             UnparkBlock(pindex);
         }
 
         // If the finalized block is on the active chain, there is no need to
         // rewind.
         if (::ChainActive().Contains(pindex)) {
             return true;
         }
 
         // If the finalized block is not on the active chain, that chain is
         // invalid
         // ...
         const CBlockIndex *pindexFork = ::ChainActive().FindFork(pindex);
         pindexToInvalidate = ::ChainActive().Next(pindexFork);
         if (!pindexToInvalidate) {
             return false;
         }
     } // end of locked cs_main scope
 
     // ... therefore, we invalidate the block on the active chain that comes
     // immediately after it
     return UnwindBlock(config, state, pindexToInvalidate,
                        true /* invalidating */);
 }
 
 template <typename F>
 bool CChainState::UpdateFlagsForBlock(CBlockIndex *pindexBase,
                                       CBlockIndex *pindex, F f) {
     BlockStatus newStatus = f(pindex->nStatus);
     if (pindex->nStatus != newStatus &&
         (!pindexBase ||
          pindex->GetAncestor(pindexBase->nHeight) == pindexBase)) {
         pindex->nStatus = newStatus;
         setDirtyBlockIndex.insert(pindex);
         if (newStatus.isValid()) {
             m_blockman.m_failed_blocks.erase(pindex);
         }
 
         if (pindex->IsValid(BlockValidity::TRANSACTIONS) &&
             pindex->HaveTxsDownloaded() &&
             setBlockIndexCandidates.value_comp()(::ChainActive().Tip(),
                                                  pindex)) {
             setBlockIndexCandidates.insert(pindex);
         }
         return true;
     }
     return false;
 }
 
 template <typename F, typename C, typename AC>
 void CChainState::UpdateFlags(CBlockIndex *pindex, CBlockIndex *&pindexReset,
                               F f, C fChild, AC fAncestorWasChanged) {
     AssertLockHeld(cs_main);
 
     // Update the current block and ancestors; while we're doing this, identify
     // which was the deepest ancestor we changed.
     CBlockIndex *pindexDeepestChanged = pindex;
     for (auto pindexAncestor = pindex; pindexAncestor != nullptr;
          pindexAncestor = pindexAncestor->pprev) {
         if (UpdateFlagsForBlock(nullptr, pindexAncestor, f)) {
             pindexDeepestChanged = pindexAncestor;
         }
     }
 
     if (pindexReset &&
         pindexReset->GetAncestor(pindexDeepestChanged->nHeight) ==
             pindexDeepestChanged) {
         // reset pindexReset if it had a modified ancestor.
         pindexReset = nullptr;
     }
 
     // Update all blocks under modified blocks.
     BlockMap::iterator it = m_blockman.m_block_index.begin();
     while (it != m_blockman.m_block_index.end()) {
         UpdateFlagsForBlock(pindex, it->second, fChild);
         UpdateFlagsForBlock(pindexDeepestChanged, it->second,
                             fAncestorWasChanged);
         it++;
     }
 }
 
 void CChainState::ResetBlockFailureFlags(CBlockIndex *pindex) {
     AssertLockHeld(cs_main);
 
     // In case we are reconsidering something before the finalization point,
     // move the finalization point to the last common ancestor.
     if (m_finalizedBlockIndex) {
         m_finalizedBlockIndex =
             LastCommonAncestor(pindex, m_finalizedBlockIndex);
     }
 
     UpdateFlags(
         pindex, pindexBestInvalid,
         [](const BlockStatus status) {
             return status.withClearedFailureFlags();
         },
         [](const BlockStatus status) {
             return status.withClearedFailureFlags();
         },
         [](const BlockStatus status) {
             return status.withFailedParent(false);
         });
 }
 
 void ResetBlockFailureFlags(CBlockIndex *pindex) {
     return ::ChainstateActive().ResetBlockFailureFlags(pindex);
 }
 
 void CChainState::UnparkBlockImpl(CBlockIndex *pindex, bool fClearChildren) {
     AssertLockHeld(cs_main);
 
     UpdateFlags(
         pindex, pindexBestParked,
         [](const BlockStatus status) {
             return status.withClearedParkedFlags();
         },
         [fClearChildren](const BlockStatus status) {
             return fClearChildren ? status.withClearedParkedFlags()
                                   : status.withParkedParent(false);
         },
         [](const BlockStatus status) {
             return status.withParkedParent(false);
         });
 }
 
 void UnparkBlockAndChildren(CBlockIndex *pindex) {
     return ::ChainstateActive().UnparkBlockImpl(pindex, true);
 }
 
 void UnparkBlock(CBlockIndex *pindex) {
     return ::ChainstateActive().UnparkBlockImpl(pindex, false);
 }
 
 bool CChainState::IsBlockFinalized(const CBlockIndex *pindex) const {
     AssertLockHeld(cs_main);
     return m_finalizedBlockIndex &&
            m_finalizedBlockIndex->GetAncestor(pindex->nHeight) == pindex;
 }
 
 /** Return the currently finalized block index. */
 const CBlockIndex *CChainState::GetFinalizedBlock() const {
     AssertLockHeld(cs_main);
     return m_finalizedBlockIndex;
 }
 
 CBlockIndex *BlockManager::AddToBlockIndex(const CBlockHeader &block) {
     AssertLockHeld(cs_main);
 
     // Check for duplicate
     BlockHash hash = block.GetHash();
     BlockMap::iterator it = m_block_index.find(hash);
     if (it != m_block_index.end()) {
         return it->second;
     }
 
     // Construct new block index object
     CBlockIndex *pindexNew = new CBlockIndex(block);
     // We assign the sequence id to blocks only when the full data is available,
     // to avoid miners withholding blocks but broadcasting headers, to get a
     // competitive advantage.
     pindexNew->nSequenceId = 0;
     BlockMap::iterator mi =
         m_block_index.insert(std::make_pair(hash, pindexNew)).first;
     pindexNew->phashBlock = &((*mi).first);
     BlockMap::iterator miPrev = m_block_index.find(block.hashPrevBlock);
     if (miPrev != m_block_index.end()) {
         pindexNew->pprev = (*miPrev).second;
         pindexNew->nHeight = pindexNew->pprev->nHeight + 1;
         pindexNew->BuildSkip();
     }
     pindexNew->nTimeReceived = GetTime();
     pindexNew->nTimeMax =
         (pindexNew->pprev
              ? std::max(pindexNew->pprev->nTimeMax, pindexNew->nTime)
              : pindexNew->nTime);
     pindexNew->nChainWork =
         (pindexNew->pprev ? pindexNew->pprev->nChainWork : 0) +
         GetBlockProof(*pindexNew);
     pindexNew->RaiseValidity(BlockValidity::TREE);
     if (pindexBestHeader == nullptr ||
         pindexBestHeader->nChainWork < pindexNew->nChainWork) {
         pindexBestHeader = pindexNew;
     }
 
     setDirtyBlockIndex.insert(pindexNew);
     return pindexNew;
 }
 
 /**
  * Mark a block as having its data received and checked (up to
  * BLOCK_VALID_TRANSACTIONS).
  */
 void CChainState::ReceivedBlockTransactions(const CBlock &block,
                                             CBlockIndex *pindexNew,
                                             const FlatFilePos &pos) {
     pindexNew->nTx = block.vtx.size();
     pindexNew->nSize = ::GetSerializeSize(block, PROTOCOL_VERSION);
     pindexNew->nFile = pos.nFile;
     pindexNew->nDataPos = pos.nPos;
     pindexNew->nUndoPos = 0;
     pindexNew->nStatus = pindexNew->nStatus.withData();
     pindexNew->RaiseValidity(BlockValidity::TRANSACTIONS);
     setDirtyBlockIndex.insert(pindexNew);
 
     if (pindexNew->UpdateChainStats()) {
         // If pindexNew is the genesis block or all parents are
         // BLOCK_VALID_TRANSACTIONS.
         std::deque<CBlockIndex *> queue;
         queue.push_back(pindexNew);
 
         // Recursively process any descendant blocks that now may be eligible to
         // be connected.
         while (!queue.empty()) {
             CBlockIndex *pindex = queue.front();
             queue.pop_front();
             pindex->UpdateChainStats();
             if (pindex->nSequenceId == 0) {
                 // We assign a sequence is when transaction are received to
                 // prevent a miner from being able to broadcast a block but not
                 // its content. However, a sequence id may have been set
                 // manually, for instance via PreciousBlock, in which case, we
                 // don't need to assign one.
                 pindex->nSequenceId = nBlockSequenceId++;
             }
 
             if (m_chain.Tip() == nullptr ||
                 !setBlockIndexCandidates.value_comp()(pindex, m_chain.Tip())) {
                 setBlockIndexCandidates.insert(pindex);
             }
 
             std::pair<std::multimap<CBlockIndex *, CBlockIndex *>::iterator,
                       std::multimap<CBlockIndex *, CBlockIndex *>::iterator>
                 range = m_blockman.m_blocks_unlinked.equal_range(pindex);
             while (range.first != range.second) {
                 std::multimap<CBlockIndex *, CBlockIndex *>::iterator it =
                     range.first;
                 queue.push_back(it->second);
                 range.first++;
                 m_blockman.m_blocks_unlinked.erase(it);
             }
         }
     } else if (pindexNew->pprev &&
                pindexNew->pprev->IsValid(BlockValidity::TREE)) {
         m_blockman.m_blocks_unlinked.insert(
             std::make_pair(pindexNew->pprev, pindexNew));
     }
 }
 
 static bool FindBlockPos(FlatFilePos &pos, unsigned int nAddSize,
                          unsigned int nHeight, uint64_t nTime,
                          bool fKnown = false) {
     LOCK(cs_LastBlockFile);
 
     unsigned int nFile = fKnown ? pos.nFile : nLastBlockFile;
     if (vinfoBlockFile.size() <= nFile) {
         vinfoBlockFile.resize(nFile + 1);
     }
 
     bool finalize_undo = false;
     if (!fKnown) {
         while (vinfoBlockFile[nFile].nSize + nAddSize >= MAX_BLOCKFILE_SIZE) {
             // when the undo file is keeping up with the block file, we want to
             // flush it explicitly when it is lagging behind (more blocks arrive
             // than are being connected), we let the undo block write case
             // handle it
             finalize_undo = (vinfoBlockFile[nFile].nHeightLast ==
                              (unsigned int)ChainActive().Tip()->nHeight);
             nFile++;
             if (vinfoBlockFile.size() <= nFile) {
                 vinfoBlockFile.resize(nFile + 1);
             }
         }
         pos.nFile = nFile;
         pos.nPos = vinfoBlockFile[nFile].nSize;
     }
 
     if ((int)nFile != nLastBlockFile) {
         if (!fKnown) {
             LogPrintf("Leaving block file %i: %s\n", nLastBlockFile,
                       vinfoBlockFile[nLastBlockFile].ToString());
         }
         FlushBlockFile(!fKnown, finalize_undo);
         nLastBlockFile = nFile;
     }
 
     vinfoBlockFile[nFile].AddBlock(nHeight, nTime);
     if (fKnown) {
         vinfoBlockFile[nFile].nSize =
             std::max(pos.nPos + nAddSize, vinfoBlockFile[nFile].nSize);
     } else {
         vinfoBlockFile[nFile].nSize += nAddSize;
     }
 
     if (!fKnown) {
         bool out_of_space;
         size_t bytes_allocated =
             BlockFileSeq().Allocate(pos, nAddSize, out_of_space);
         if (out_of_space) {
             return AbortNode("Disk space is too low!",
                              _("Disk space is too low!"));
         }
         if (bytes_allocated != 0 && fPruneMode) {
             fCheckForPruning = true;
         }
     }
 
     setDirtyFileInfo.insert(nFile);
     return true;
 }
 
 static bool FindUndoPos(BlockValidationState &state, int nFile,
                         FlatFilePos &pos, unsigned int nAddSize) {
     pos.nFile = nFile;
 
     LOCK(cs_LastBlockFile);
 
     pos.nPos = vinfoBlockFile[nFile].nUndoSize;
     vinfoBlockFile[nFile].nUndoSize += nAddSize;
     setDirtyFileInfo.insert(nFile);
 
     bool out_of_space;
     size_t bytes_allocated =
         UndoFileSeq().Allocate(pos, nAddSize, out_of_space);
     if (out_of_space) {
         return AbortNode(state, "Disk space is too low!",
                          _("Disk space is too low!"));
     }
     if (bytes_allocated != 0 && fPruneMode) {
         fCheckForPruning = true;
     }
 
     return true;
 }
 
 /**
  * Return true if the provided block header is valid.
  * Only verify PoW if blockValidationOptions is configured to do so.
  * This allows validation of headers on which the PoW hasn't been done.
  * For example: to validate template handed to mining software.
  * Do not call this for any check that depends on the context.
  * For context-dependent calls, see ContextualCheckBlockHeader.
  */
 static bool CheckBlockHeader(const CBlockHeader &block,
                              BlockValidationState &state,
                              const Consensus::Params &params,
                              BlockValidationOptions validationOptions) {
     // Check proof of work matches claimed amount
     if (validationOptions.shouldValidatePoW() &&
         !CheckProofOfWork(block.GetHash(), block.nBits, params)) {
         return state.Invalid(BlockValidationResult::BLOCK_INVALID_HEADER,
                              "high-hash", "proof of work failed");
     }
 
     return true;
 }
 
 bool CheckBlock(const CBlock &block, BlockValidationState &state,
                 const Consensus::Params &params,
                 BlockValidationOptions validationOptions) {
     // These are checks that are independent of context.
     if (block.fChecked) {
         return true;
     }
 
     // Check that the header is valid (particularly PoW).  This is mostly
     // redundant with the call in AcceptBlockHeader.
     if (!CheckBlockHeader(block, state, params, validationOptions)) {
         return false;
     }
 
     // Check the merkle root.
     if (validationOptions.shouldValidateMerkleRoot()) {
         bool mutated;
         uint256 hashMerkleRoot2 = BlockMerkleRoot(block, &mutated);
         if (block.hashMerkleRoot != hashMerkleRoot2) {
             return state.Invalid(BlockValidationResult::BLOCK_MUTATED,
                                  "bad-txnmrklroot", "hashMerkleRoot mismatch");
         }
 
         // Check for merkle tree malleability (CVE-2012-2459): repeating
         // sequences of transactions in a block without affecting the merkle
         // root of a block, while still invalidating it.
         if (mutated) {
             return state.Invalid(BlockValidationResult::BLOCK_MUTATED,
                                  "bad-txns-duplicate", "duplicate transaction");
         }
     }
 
     // All potential-corruption validation must be done before we do any
     // transaction validation, as otherwise we may mark the header as invalid
     // because we receive the wrong transactions for it.
 
     // First transaction must be coinbase.
     if (block.vtx.empty()) {
         return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS,
                              "bad-cb-missing", "first tx is not coinbase");
     }
 
     // Size limits.
     auto nMaxBlockSize = validationOptions.getExcessiveBlockSize();
 
     // Bail early if there is no way this block is of reasonable size.
     if ((block.vtx.size() * MIN_TRANSACTION_SIZE) > nMaxBlockSize) {
         return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS,
                              "bad-blk-length", "size limits failed");
     }
 
     auto currentBlockSize = ::GetSerializeSize(block, PROTOCOL_VERSION);
     if (currentBlockSize > nMaxBlockSize) {
         return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS,
                              "bad-blk-length", "size limits failed");
     }
 
     // And a valid coinbase.
     TxValidationState tx_state;
     if (!CheckCoinbase(*block.vtx[0], tx_state)) {
         return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS,
                              tx_state.GetRejectReason(),
                              strprintf("Coinbase check failed (txid %s) %s",
                                        block.vtx[0]->GetId().ToString(),
                                        tx_state.GetDebugMessage()));
     }
 
     // Check transactions for regularity, skipping the first. Note that this
     // is the first time we check that all after the first are !IsCoinBase.
     for (size_t i = 1; i < block.vtx.size(); i++) {
         auto *tx = block.vtx[i].get();
         if (!CheckRegularTransaction(*tx, tx_state)) {
             return state.Invalid(
                 BlockValidationResult::BLOCK_CONSENSUS,
                 tx_state.GetRejectReason(),
                 strprintf("Transaction check failed (txid %s) %s",
                           tx->GetId().ToString(), tx_state.GetDebugMessage()));
         }
     }
 
     if (validationOptions.shouldValidatePoW() &&
         validationOptions.shouldValidateMerkleRoot()) {
         block.fChecked = true;
     }
 
     return true;
 }
 
 /**
  * Context-dependent validity checks.
  * By "context", we mean only the previous block headers, but not the UTXO
  * set; UTXO-related validity checks are done in ConnectBlock().
  * NOTE: This function is not currently invoked by ConnectBlock(), so we
  * should consider upgrade issues if we change which consensus rules are
  * enforced in this function (eg by adding a new consensus rule). See comment
  * in ConnectBlock().
  * Note that -reindex-chainstate skips the validation that happens here!
  */
 static bool ContextualCheckBlockHeader(const CChainParams &params,
                                        const CBlockHeader &block,
                                        BlockValidationState &state,
                                        const CBlockIndex *pindexPrev,
                                        int64_t nAdjustedTime)
     EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
     assert(pindexPrev != nullptr);
     const int nHeight = pindexPrev->nHeight + 1;
 
     // Check proof of work
     if (block.nBits != GetNextWorkRequired(pindexPrev, &block, params)) {
         LogPrintf("bad bits after height: %d\n", pindexPrev->nHeight);
         return state.Invalid(BlockValidationResult::BLOCK_INVALID_HEADER,
                              "bad-diffbits", "incorrect proof of work");
     }
 
     // Check against checkpoints
     if (fCheckpointsEnabled) {
         const CCheckpointData &checkpoints = params.Checkpoints();
 
         // Check that the block chain matches the known block chain up to a
         // checkpoint.
         if (!Checkpoints::CheckBlock(checkpoints, nHeight, block.GetHash())) {
             LogPrintf("ERROR: %s: rejected by checkpoint lock-in at %d\n",
                       __func__, nHeight);
             return state.Invalid(BlockValidationResult::BLOCK_CHECKPOINT,
                                  "checkpoint mismatch");
         }
 
         // Don't accept any forks from the main chain prior to last checkpoint.
         // GetLastCheckpoint finds the last checkpoint in MapCheckpoints that's
         // in our BlockIndex().
         CBlockIndex *pcheckpoint = Checkpoints::GetLastCheckpoint(checkpoints);
         if (pcheckpoint && nHeight < pcheckpoint->nHeight) {
             LogPrintf("ERROR: %s: forked chain older than last checkpoint "
                       "(height %d)\n",
                       __func__, nHeight);
             return state.Invalid(BlockValidationResult::BLOCK_CHECKPOINT,
                                  "bad-fork-prior-to-checkpoint");
         }
     }
 
     // Check timestamp against prev
     if (block.GetBlockTime() <= pindexPrev->GetMedianTimePast()) {
         return state.Invalid(BlockValidationResult::BLOCK_INVALID_HEADER,
                              "time-too-old", "block's timestamp is too early");
     }
 
     // Check timestamp
     if (block.GetBlockTime() > nAdjustedTime + MAX_FUTURE_BLOCK_TIME) {
         return state.Invalid(BlockValidationResult::BLOCK_TIME_FUTURE,
                              "time-too-new",
                              "block timestamp too far in the future");
     }
 
     // Reject outdated version blocks when 95% (75% on testnet) of the network
     // has upgraded:
     // check for version 2, 3 and 4 upgrades
     const Consensus::Params &consensusParams = params.GetConsensus();
     if ((block.nVersion < 2 && nHeight >= consensusParams.BIP34Height) ||
         (block.nVersion < 3 && nHeight >= consensusParams.BIP66Height) ||
         (block.nVersion < 4 && nHeight >= consensusParams.BIP65Height)) {
         return state.Invalid(
             BlockValidationResult::BLOCK_INVALID_HEADER,
             strprintf("bad-version(0x%08x)", block.nVersion),
             strprintf("rejected nVersion=0x%08x block", block.nVersion));
     }
 
     return true;
 }
 
 bool ContextualCheckTransactionForCurrentBlock(const Consensus::Params &params,
                                                const CTransaction &tx,
                                                TxValidationState &state,
                                                int flags) {
     AssertLockHeld(cs_main);
 
     // By convention a negative value for flags indicates that the current
     // network-enforced consensus rules should be used. In a future soft-fork
     // scenario that would mean checking which rules would be enforced for the
     // next block and setting the appropriate flags. At the present time no
     // soft-forks are scheduled, so no flags are set.
     flags = std::max(flags, 0);
 
     // ContextualCheckTransactionForCurrentBlock() uses
     // ::ChainActive().Height()+1 to evaluate nLockTime because when IsFinalTx()
     // is called within CBlock::AcceptBlock(), the height of the block *being*
     // evaluated is what is used. Thus if we want to know if a transaction can
     // be part of the *next* block, we need to call ContextualCheckTransaction()
     // with one more than ::ChainActive().Height().
     const int nBlockHeight = ::ChainActive().Height() + 1;
 
     // BIP113 will require that time-locked transactions have nLockTime set to
     // less than the median time of the previous block they're contained in.
     // When the next block is created its previous block will be the current
     // chain tip, so we use that to calculate the median time passed to
     // ContextualCheckTransaction() if LOCKTIME_MEDIAN_TIME_PAST is set.
     const int64_t nMedianTimePast =
         ::ChainActive().Tip() == nullptr
             ? 0
             : ::ChainActive().Tip()->GetMedianTimePast();
     const int64_t nLockTimeCutoff = (flags & LOCKTIME_MEDIAN_TIME_PAST)
                                         ? nMedianTimePast
                                         : GetAdjustedTime();
 
     return ContextualCheckTransaction(params, tx, state, nBlockHeight,
                                       nLockTimeCutoff, nMedianTimePast);
 }
 
 /**
  * NOTE: This function is not currently invoked by ConnectBlock(), so we
  * should consider upgrade issues if we change which consensus rules are
  * enforced in this function (eg by adding a new consensus rule). See comment
  * in ConnectBlock().
  * Note that -reindex-chainstate skips the validation that happens here!
  */
 static bool ContextualCheckBlock(const CBlock &block,
                                  BlockValidationState &state,
                                  const Consensus::Params &params,
                                  const CBlockIndex *pindexPrev) {
     const int nHeight = pindexPrev == nullptr ? 0 : pindexPrev->nHeight + 1;
 
     // Start enforcing BIP113 (Median Time Past).
     int nLockTimeFlags = 0;
     if (nHeight >= params.CSVHeight) {
         assert(pindexPrev != nullptr);
         nLockTimeFlags |= LOCKTIME_MEDIAN_TIME_PAST;
     }
 
     const int64_t nMedianTimePast =
         pindexPrev == nullptr ? 0 : pindexPrev->GetMedianTimePast();
 
     const int64_t nLockTimeCutoff = (nLockTimeFlags & LOCKTIME_MEDIAN_TIME_PAST)
                                         ? nMedianTimePast
                                         : block.GetBlockTime();
 
     const bool fIsMagneticAnomalyEnabled =
         IsMagneticAnomalyEnabled(params, pindexPrev);
 
     // Check transactions:
     // - canonical ordering
     // - ensure they are finalized
     // - perform a preliminary block-sigops count (they will be recounted more
     // strictly during ConnectBlock).
     // - perform a transaction-sigops check (again, a more strict check will
     // happen in ConnectBlock).
     const CTransaction *prevTx = nullptr;
     for (const auto &ptx : block.vtx) {
         const CTransaction &tx = *ptx;
         if (fIsMagneticAnomalyEnabled) {
             if (prevTx && (tx.GetId() <= prevTx->GetId())) {
                 if (tx.GetId() == prevTx->GetId()) {
                     return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS,
                                          "tx-duplicate",
                                          strprintf("Duplicated transaction %s",
                                                    tx.GetId().ToString()));
                 }
 
                 return state.Invalid(
                     BlockValidationResult::BLOCK_CONSENSUS, "tx-ordering",
                     strprintf("Transaction order is invalid (%s < %s)",
                               tx.GetId().ToString(),
                               prevTx->GetId().ToString()));
             }
 
             if (prevTx || !tx.IsCoinBase()) {
                 prevTx = &tx;
             }
         }
 
         TxValidationState tx_state;
         if (!ContextualCheckTransaction(params, tx, tx_state, nHeight,
                                         nLockTimeCutoff, nMedianTimePast)) {
             return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS,
                                  tx_state.GetRejectReason(),
                                  tx_state.GetDebugMessage());
         }
     }
 
     // Enforce rule that the coinbase starts with serialized block height
     if (nHeight >= params.BIP34Height) {
         CScript expect = CScript() << nHeight;
         if (block.vtx[0]->vin[0].scriptSig.size() < expect.size() ||
             !std::equal(expect.begin(), expect.end(),
                         block.vtx[0]->vin[0].scriptSig.begin())) {
             return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS,
                                  "bad-cb-height",
                                  "block height mismatch in coinbase");
         }
     }
 
     return true;
 }
 
 /**
  * If the provided block header is valid, add it to the block index.
  *
  * Returns true if the block is successfully added to the block index.
  */
 bool BlockManager::AcceptBlockHeader(const Config &config,
                                      const CBlockHeader &block,
                                      BlockValidationState &state,
                                      CBlockIndex **ppindex) {
     AssertLockHeld(cs_main);
     const CChainParams &chainparams = config.GetChainParams();
 
     // Check for duplicate
     BlockHash hash = block.GetHash();
     BlockMap::iterator miSelf = m_block_index.find(hash);
     CBlockIndex *pindex = nullptr;
     if (hash != chainparams.GetConsensus().hashGenesisBlock) {
         if (miSelf != m_block_index.end()) {
             // Block header is already known.
             pindex = miSelf->second;
             if (ppindex) {
                 *ppindex = pindex;
             }
 
             if (pindex->nStatus.isInvalid()) {
                 LogPrintf("ERROR: %s: block %s is marked invalid\n", __func__,
                           hash.ToString());
                 return state.Invalid(
                     BlockValidationResult::BLOCK_CACHED_INVALID, "duplicate");
             }
 
             return true;
         }
 
         if (!CheckBlockHeader(block, state, chainparams.GetConsensus(),
                               BlockValidationOptions(config))) {
             LogPrint(BCLog::VALIDATION,
                      "%s: Consensus::CheckBlockHeader: %s, %s\n", __func__,
                      hash.ToString(), state.ToString());
             return false;
         }
 
         // Get prev block index
         BlockMap::iterator mi = m_block_index.find(block.hashPrevBlock);
         if (mi == m_block_index.end()) {
             LogPrintf("ERROR: %s: prev block not found\n", __func__);
             return state.Invalid(BlockValidationResult::BLOCK_MISSING_PREV,
                                  "prev-blk-not-found");
         }
 
         CBlockIndex *pindexPrev = (*mi).second;
         assert(pindexPrev);
         if (pindexPrev->nStatus.isInvalid()) {
             LogPrintf("ERROR: %s: prev block invalid\n", __func__);
             return state.Invalid(BlockValidationResult::BLOCK_INVALID_PREV,
                                  "bad-prevblk");
         }
 
         if (!ContextualCheckBlockHeader(chainparams, block, state, pindexPrev,
                                         GetAdjustedTime())) {
             return error("%s: Consensus::ContextualCheckBlockHeader: %s, %s",
                          __func__, hash.ToString(), state.ToString());
         }
 
         /* Determine if this block descends from any block which has been found
          * invalid (m_failed_blocks), then mark pindexPrev and any blocks
          * between them as failed. For example:
          *
          *                D3
          *              /
          *      B2 - C2
          *    /         \
          *  A             D2 - E2 - F2
          *    \
          *      B1 - C1 - D1 - E1
          *
          * In the case that we attempted to reorg from E1 to F2, only to find
          * C2 to be invalid, we would mark D2, E2, and F2 as BLOCK_FAILED_CHILD
          * but NOT D3 (it was not in any of our candidate sets at the time).
          *
          * In any case D3 will also be marked as BLOCK_FAILED_CHILD at restart
          * in LoadBlockIndex.
          */
         if (!pindexPrev->IsValid(BlockValidity::SCRIPTS)) {
             // The above does not mean "invalid": it checks if the previous
             // block hasn't been validated up to BlockValidity::SCRIPTS. This is
             // a performance optimization, in the common case of adding a new
             // block to the tip, we don't need to iterate over the failed blocks
             // list.
             for (const CBlockIndex *failedit : m_failed_blocks) {
                 if (pindexPrev->GetAncestor(failedit->nHeight) == failedit) {
                     assert(failedit->nStatus.hasFailed());
                     CBlockIndex *invalid_walk = pindexPrev;
                     while (invalid_walk != failedit) {
                         invalid_walk->nStatus =
                             invalid_walk->nStatus.withFailedParent();
                         setDirtyBlockIndex.insert(invalid_walk);
                         invalid_walk = invalid_walk->pprev;
                     }
                     LogPrintf("ERROR: %s: prev block invalid\n", __func__);
                     return state.Invalid(
                         BlockValidationResult::BLOCK_INVALID_PREV,
                         "bad-prevblk");
                 }
             }
         }
     }
 
     if (pindex == nullptr) {
         pindex = AddToBlockIndex(block);
     }
 
     if (ppindex) {
         *ppindex = pindex;
     }
 
     return true;
 }
 
 // Exposed wrapper for AcceptBlockHeader
 bool ChainstateManager::ProcessNewBlockHeaders(
     const Config &config, const std::vector<CBlockHeader> &headers,
     BlockValidationState &state, const CBlockIndex **ppindex) {
     AssertLockNotHeld(cs_main);
     {
         LOCK(cs_main);
         for (const CBlockHeader &header : headers) {
             // Use a temp pindex instead of ppindex to avoid a const_cast
             CBlockIndex *pindex = nullptr;
             bool accepted =
                 m_blockman.AcceptBlockHeader(config, header, state, &pindex);
             ::ChainstateActive().CheckBlockIndex(
                 config.GetChainParams().GetConsensus());
 
             if (!accepted) {
                 return false;
             }
 
             if (ppindex) {
                 *ppindex = pindex;
             }
         }
     }
 
     if (NotifyHeaderTip()) {
         if (::ChainstateActive().IsInitialBlockDownload() && ppindex &&
             *ppindex) {
             LogPrintf("Synchronizing blockheaders, height: %d (~%.2f%%)\n",
                       (*ppindex)->nHeight,
                       100.0 /
                           ((*ppindex)->nHeight +
                            (GetAdjustedTime() - (*ppindex)->GetBlockTime()) /
                                Params().GetConsensus().nPowTargetSpacing) *
                           (*ppindex)->nHeight);
         }
     }
     return true;
 }
 
 /**
  * Store block on disk. If dbp is non-nullptr, the file is known to already
  * reside on disk.
  */
 static FlatFilePos SaveBlockToDisk(const CBlock &block, int nHeight,
                                    const CChainParams &chainparams,
                                    const FlatFilePos *dbp) {
     unsigned int nBlockSize = ::GetSerializeSize(block, CLIENT_VERSION);
     FlatFilePos blockPos;
     if (dbp != nullptr) {
         blockPos = *dbp;
     }
     if (!FindBlockPos(blockPos, nBlockSize + 8, nHeight, block.GetBlockTime(),
                       dbp != nullptr)) {
         error("%s: FindBlockPos failed", __func__);
         return FlatFilePos();
     }
     if (dbp == nullptr) {
         if (!WriteBlockToDisk(block, blockPos, chainparams.DiskMagic())) {
             AbortNode("Failed to write block");
             return FlatFilePos();
         }
     }
     return blockPos;
 }
 
 /**
  * Store a block on disk.
  *
  * @param[in]     config     The global config.
  * @param[in-out] pblock     The block we want to accept.
  * @param[in]     fRequested A boolean to indicate if this block was requested
  *                           from our peers.
  * @param[in]     dbp        If non-null, the disk position of the block.
  * @param[in-out] fNewBlock  True if block was first received via this call.
  * @return True if the block is accepted as a valid block and written to disk.
  */
 bool CChainState::AcceptBlock(const Config &config,
                               const std::shared_ptr<const CBlock> &pblock,
                               BlockValidationState &state, bool fRequested,
                               const FlatFilePos *dbp, bool *fNewBlock) {
     AssertLockHeld(cs_main);
 
     const CBlock &block = *pblock;
     if (fNewBlock) {
         *fNewBlock = false;
     }
 
     CBlockIndex *pindex = nullptr;
 
     bool accepted_header =
         m_blockman.AcceptBlockHeader(config, block, state, &pindex);
     CheckBlockIndex(config.GetChainParams().GetConsensus());
 
     if (!accepted_header) {
         return false;
     }
 
     // Try to process all requested blocks that we don't have, but only
     // process an unrequested block if it's new and has enough work to
     // advance our tip, and isn't too many blocks ahead.
     bool fAlreadyHave = pindex->nStatus.hasData();
 
     // TODO: deal better with return value and error conditions for duplicate
     // and unrequested blocks.
     if (fAlreadyHave) {
         return true;
     }
 
     // Compare block header timestamps and received times of the block and the
     // chaintip.  If they have the same chain height, use these diffs as a
     // tie-breaker, attempting to pick the more honestly-mined block.
     int64_t newBlockTimeDiff = std::llabs(pindex->GetReceivedTimeDiff());
     int64_t chainTipTimeDiff =
         m_chain.Tip() ? std::llabs(m_chain.Tip()->GetReceivedTimeDiff()) : 0;
 
     bool isSameHeight =
         m_chain.Tip() && (pindex->nChainWork == m_chain.Tip()->nChainWork);
     if (isSameHeight) {
         LogPrintf("Chain tip timestamp-to-received-time difference: hash=%s, "
                   "diff=%d\n",
                   m_chain.Tip()->GetBlockHash().ToString(), chainTipTimeDiff);
         LogPrintf("New block timestamp-to-received-time difference: hash=%s, "
                   "diff=%d\n",
                   pindex->GetBlockHash().ToString(), newBlockTimeDiff);
     }
 
     bool fHasMoreOrSameWork =
         (m_chain.Tip() ? pindex->nChainWork >= m_chain.Tip()->nChainWork
                        : true);
 
     // Blocks that are too out-of-order needlessly limit the effectiveness of
     // pruning, because pruning will not delete block files that contain any
     // blocks which are too close in height to the tip.  Apply this test
     // regardless of whether pruning is enabled; it should generally be safe to
     // not process unrequested blocks.
     bool fTooFarAhead =
         (pindex->nHeight > int(m_chain.Height() + MIN_BLOCKS_TO_KEEP));
 
     // TODO: Decouple this function from the block download logic by removing
     // fRequested
     // This requires some new chain data structure to efficiently look up if a
     // block is in a chain leading to a candidate for best tip, despite not
     // being such a candidate itself.
 
     // If we didn't ask for it:
     if (!fRequested) {
         // This is a previously-processed block that was pruned.
         if (pindex->nTx != 0) {
             return true;
         }
 
         // Don't process less-work chains.
         if (!fHasMoreOrSameWork) {
             return true;
         }
 
         // Block height is too high.
         if (fTooFarAhead) {
             return true;
         }
 
         // Protect against DoS attacks from low-work chains.
         // If our tip is behind, a peer could try to send us
         // low-work blocks on a fake chain that we would never
         // request; don't process these.
         if (pindex->nChainWork < nMinimumChainWork) {
             return true;
         }
     }
 
     const CChainParams &chainparams = config.GetChainParams();
     const Consensus::Params &consensusParams = chainparams.GetConsensus();
 
     if (!CheckBlock(block, state, consensusParams,
                     BlockValidationOptions(config)) ||
         !ContextualCheckBlock(block, state, consensusParams, pindex->pprev)) {
         if (state.IsInvalid() &&
             state.GetResult() != BlockValidationResult::BLOCK_MUTATED) {
             pindex->nStatus = pindex->nStatus.withFailed();
             setDirtyBlockIndex.insert(pindex);
         }
 
         return error("%s: %s (block %s)", __func__, state.ToString(),
                      block.GetHash().ToString());
     }
 
     // If connecting the new block would require rewinding more than one block
     // from the active chain (i.e., a "deep reorg"), then mark the new block as
     // parked. If it has enough work then it will be automatically unparked
     // later, during FindMostWorkChain. We mark the block as parked at the very
     // last minute so we can make sure everything is ready to be reorged if
     // needed.
     if (gArgs.GetBoolArg("-parkdeepreorg", true)) {
         const CBlockIndex *pindexFork = m_chain.FindFork(pindex);
         if (pindexFork && pindexFork->nHeight + 1 < m_chain.Height()) {
             LogPrintf("Park block %s as it would cause a deep reorg.\n",
                       pindex->GetBlockHash().ToString());
             pindex->nStatus = pindex->nStatus.withParked();
             setDirtyBlockIndex.insert(pindex);
         }
     }
 
     // Header is valid/has work and the merkle tree is good.
     // Relay now, but if it does not build on our best tip, let the
     // SendMessages loop relay it.
     if (!IsInitialBlockDownload() && m_chain.Tip() == pindex->pprev) {
         GetMainSignals().NewPoWValidBlock(pindex, pblock);
     }
 
     // Write block to history file
     if (fNewBlock) {
         *fNewBlock = true;
     }
     try {
         FlatFilePos blockPos =
             SaveBlockToDisk(block, pindex->nHeight, chainparams, dbp);
         if (blockPos.IsNull()) {
             state.Error(strprintf(
                 "%s: Failed to find position to write new block to disk",
                 __func__));
             return false;
         }
         ReceivedBlockTransactions(block, pindex, blockPos);
     } catch (const std::runtime_error &e) {
         return AbortNode(state, std::string("System error: ") + e.what());
     }
 
     FlushStateToDisk(chainparams, state, FlushStateMode::NONE);
 
     CheckBlockIndex(consensusParams);
 
     return true;
 }
 
 bool ChainstateManager::ProcessNewBlock(
     const Config &config, const std::shared_ptr<const CBlock> pblock,
     bool fForceProcessing, bool *fNewBlock) {
     AssertLockNotHeld(cs_main);
 
     {
         if (fNewBlock) {
             *fNewBlock = false;
         }
 
         BlockValidationState state;
 
         // CheckBlock() does not support multi-threaded block validation
         // because CBlock::fChecked can cause data race.
         // Therefore, the following critical section must include the
         // CheckBlock() call as well.
         LOCK(cs_main);
 
         // Ensure that CheckBlock() passes before calling AcceptBlock, as
         // belt-and-suspenders.
         bool ret =
             CheckBlock(*pblock, state, config.GetChainParams().GetConsensus(),
                        BlockValidationOptions(config));
         if (ret) {
             // Store to disk
             ret = ::ChainstateActive().AcceptBlock(
                 config, pblock, state, fForceProcessing, nullptr, fNewBlock);
         }
 
         if (!ret) {
             GetMainSignals().BlockChecked(*pblock, state);
             return error("%s: AcceptBlock FAILED (%s)", __func__,
                          state.ToString());
         }
     }
 
     NotifyHeaderTip();
 
     // Only used to report errors, not invalidity - ignore it
     BlockValidationState state;
     if (!::ChainstateActive().ActivateBestChain(config, state, pblock)) {
         return error("%s: ActivateBestChain failed (%s)", __func__,
                      state.ToString());
     }
 
     return true;
 }
 
 bool TestBlockValidity(BlockValidationState &state, const CChainParams &params,
                        const CBlock &block, CBlockIndex *pindexPrev,
                        BlockValidationOptions validationOptions) {
     AssertLockHeld(cs_main);
     assert(pindexPrev && pindexPrev == ::ChainActive().Tip());
     CCoinsViewCache viewNew(&::ChainstateActive().CoinsTip());
     BlockHash block_hash(block.GetHash());
     CBlockIndex indexDummy(block);
     indexDummy.pprev = pindexPrev;
     indexDummy.nHeight = pindexPrev->nHeight + 1;
     indexDummy.phashBlock = &block_hash;
 
     // NOTE: CheckBlockHeader is called by CheckBlock
     if (!ContextualCheckBlockHeader(params, block, state, pindexPrev,
                                     GetAdjustedTime())) {
         return error("%s: Consensus::ContextualCheckBlockHeader: %s", __func__,
                      state.ToString());
     }
 
     if (!CheckBlock(block, state, params.GetConsensus(), validationOptions)) {
         return error("%s: Consensus::CheckBlock: %s", __func__,
                      state.ToString());
     }
 
     if (!ContextualCheckBlock(block, state, params.GetConsensus(),
                               pindexPrev)) {
         return error("%s: Consensus::ContextualCheckBlock: %s", __func__,
                      state.ToString());
     }
 
     if (!::ChainstateActive().ConnectBlock(block, state, &indexDummy, viewNew,
                                            params, validationOptions, true)) {
         return false;
     }
 
     assert(state.IsValid());
     return true;
 }
 
 /**
  * BLOCK PRUNING CODE
  */
 
 /**
  * Calculate the amount of disk space the block & undo files currently use.
  */
 uint64_t CalculateCurrentUsage() {
     LOCK(cs_LastBlockFile);
 
     uint64_t retval = 0;
     for (const CBlockFileInfo &file : vinfoBlockFile) {
         retval += file.nSize + file.nUndoSize;
     }
 
     return retval;
 }
 
 void BlockManager::PruneOneBlockFile(const int fileNumber) {
     AssertLockHeld(cs_main);
     LOCK(cs_LastBlockFile);
 
     for (const auto &entry : m_block_index) {
         CBlockIndex *pindex = entry.second;
         if (pindex->nFile == fileNumber) {
             pindex->nStatus = pindex->nStatus.withData(false).withUndo(false);
             pindex->nFile = 0;
             pindex->nDataPos = 0;
             pindex->nUndoPos = 0;
             setDirtyBlockIndex.insert(pindex);
 
             // Prune from m_blocks_unlinked -- any block we prune would have
             // to be downloaded again in order to consider its chain, at which
             // point it would be considered as a candidate for
             // m_blocks_unlinked or setBlockIndexCandidates.
             auto range = m_blocks_unlinked.equal_range(pindex->pprev);
             while (range.first != range.second) {
                 std::multimap<CBlockIndex *, CBlockIndex *>::iterator _it =
                     range.first;
                 range.first++;
                 if (_it->second == pindex) {
                     m_blocks_unlinked.erase(_it);
                 }
             }
         }
     }
 
     vinfoBlockFile[fileNumber].SetNull();
     setDirtyFileInfo.insert(fileNumber);
 }
 
 void UnlinkPrunedFiles(const std::set<int> &setFilesToPrune) {
     for (const int i : setFilesToPrune) {
         FlatFilePos pos(i, 0);
         fs::remove(BlockFileSeq().FileName(pos));
         fs::remove(UndoFileSeq().FileName(pos));
         LogPrintf("Prune: %s deleted blk/rev (%05u)\n", __func__, i);
     }
 }
 
 void BlockManager::FindFilesToPruneManual(std::set<int> &setFilesToPrune,
                                           int nManualPruneHeight,
                                           int chain_tip_height) {
     assert(fPruneMode && nManualPruneHeight > 0);
 
     LOCK2(cs_main, cs_LastBlockFile);
     if (chain_tip_height < 0) {
         return;
     }
 
     // last block to prune is the lesser of (user-specified height,
     // MIN_BLOCKS_TO_KEEP from the tip)
     unsigned int nLastBlockWeCanPrune = std::min(
         (unsigned)nManualPruneHeight, chain_tip_height - MIN_BLOCKS_TO_KEEP);
     int count = 0;
     for (int fileNumber = 0; fileNumber < nLastBlockFile; fileNumber++) {
         if (vinfoBlockFile[fileNumber].nSize == 0 ||
             vinfoBlockFile[fileNumber].nHeightLast > nLastBlockWeCanPrune) {
             continue;
         }
         PruneOneBlockFile(fileNumber);
         setFilesToPrune.insert(fileNumber);
         count++;
     }
     LogPrintf("Prune (Manual): prune_height=%d removed %d blk/rev pairs\n",
               nLastBlockWeCanPrune, count);
 }
 
 /* This function is called from the RPC code for pruneblockchain */
 void PruneBlockFilesManual(int nManualPruneHeight) {
     BlockValidationState state;
     const CChainParams &chainparams = Params();
     if (!::ChainstateActive().FlushStateToDisk(
             chainparams, state, FlushStateMode::NONE, nManualPruneHeight)) {
         LogPrintf("%s: failed to flush state (%s)\n", __func__,
                   state.ToString());
     }
 }
 
 void BlockManager::FindFilesToPrune(std::set<int> &setFilesToPrune,
                                     uint64_t nPruneAfterHeight,
                                     int chain_tip_height, bool is_ibd) {
     LOCK2(cs_main, cs_LastBlockFile);
     if (chain_tip_height < 0 || nPruneTarget == 0) {
         return;
     }
     if (uint64_t(chain_tip_height) <= nPruneAfterHeight) {
         return;
     }
 
     unsigned int nLastBlockWeCanPrune = chain_tip_height - MIN_BLOCKS_TO_KEEP;
     uint64_t nCurrentUsage = CalculateCurrentUsage();
     // We don't check to prune until after we've allocated new space for files,
     // so we should leave a buffer under our target to account for another
     // allocation before the next pruning.
     uint64_t nBuffer = BLOCKFILE_CHUNK_SIZE + UNDOFILE_CHUNK_SIZE;
     uint64_t nBytesToPrune;
     int count = 0;
 
     if (nCurrentUsage + nBuffer >= nPruneTarget) {
         // On a prune event, the chainstate DB is flushed.
         // To avoid excessive prune events negating the benefit of high dbcache
         // values, we should not prune too rapidly.
         // So when pruning in IBD, increase the buffer a bit to avoid a re-prune
         // too soon.
         if (is_ibd) {
             // Since this is only relevant during IBD, we use a fixed 10%
             nBuffer += nPruneTarget / 10;
         }
 
         for (int fileNumber = 0; fileNumber < nLastBlockFile; fileNumber++) {
             nBytesToPrune = vinfoBlockFile[fileNumber].nSize +
                             vinfoBlockFile[fileNumber].nUndoSize;
 
             if (vinfoBlockFile[fileNumber].nSize == 0) {
                 continue;
             }
 
             // are we below our target?
             if (nCurrentUsage + nBuffer < nPruneTarget) {
                 break;
             }
 
             // don't prune files that could have a block within
             // MIN_BLOCKS_TO_KEEP of the main chain's tip but keep scanning
             if (vinfoBlockFile[fileNumber].nHeightLast > nLastBlockWeCanPrune) {
                 continue;
             }
 
             PruneOneBlockFile(fileNumber);
             // Queue up the files for removal
             setFilesToPrune.insert(fileNumber);
             nCurrentUsage -= nBytesToPrune;
             count++;
         }
     }
 
     LogPrint(BCLog::PRUNE,
              "Prune: target=%dMiB actual=%dMiB diff=%dMiB "
              "max_prune_height=%d removed %d blk/rev pairs\n",
              nPruneTarget / 1024 / 1024, nCurrentUsage / 1024 / 1024,
              ((int64_t)nPruneTarget - (int64_t)nCurrentUsage) / 1024 / 1024,
              nLastBlockWeCanPrune, count);
 }
 
 CBlockIndex *BlockManager::InsertBlockIndex(const BlockHash &hash) {
     AssertLockHeld(cs_main);
 
     if (hash.IsNull()) {
         return nullptr;
     }
 
     // Return existing
     BlockMap::iterator mi = m_block_index.find(hash);
     if (mi != m_block_index.end()) {
         return (*mi).second;
     }
 
     // Create new
     CBlockIndex *pindexNew = new CBlockIndex();
     mi = m_block_index.insert(std::make_pair(hash, pindexNew)).first;
     pindexNew->phashBlock = &((*mi).first);
 
     return pindexNew;
 }
 
 bool BlockManager::LoadBlockIndex(
     const Consensus::Params &params, CBlockTreeDB &blocktree,
     std::set<CBlockIndex *, CBlockIndexWorkComparator>
         &block_index_candidates) {
     AssertLockHeld(cs_main);
     if (!blocktree.LoadBlockIndexGuts(
             params, [this](const BlockHash &hash) EXCLUSIVE_LOCKS_REQUIRED(
                         cs_main) { return this->InsertBlockIndex(hash); })) {
         return false;
     }
 
     // Calculate nChainWork
     std::vector<std::pair<int, CBlockIndex *>> vSortedByHeight;
     vSortedByHeight.reserve(m_block_index.size());
     for (const std::pair<const BlockHash, CBlockIndex *> &item :
          m_block_index) {
         CBlockIndex *pindex = item.second;
         vSortedByHeight.push_back(std::make_pair(pindex->nHeight, pindex));
     }
 
     sort(vSortedByHeight.begin(), vSortedByHeight.end());
     for (const std::pair<int, CBlockIndex *> &item : vSortedByHeight) {
         if (ShutdownRequested()) {
             return false;
         }
         CBlockIndex *pindex = item.second;
         pindex->nChainWork = (pindex->pprev ? pindex->pprev->nChainWork : 0) +
                              GetBlockProof(*pindex);
         pindex->nTimeMax =
             (pindex->pprev ? std::max(pindex->pprev->nTimeMax, pindex->nTime)
                            : pindex->nTime);
         // We can link the chain of blocks for which we've received transactions
         // at some point. Pruned nodes may have deleted the block.
         if (pindex->nTx > 0) {
             if (!pindex->UpdateChainStats() && pindex->pprev) {
                 m_blocks_unlinked.insert(std::make_pair(pindex->pprev, pindex));
             }
         }
 
         if (!pindex->nStatus.hasFailed() && pindex->pprev &&
             pindex->pprev->nStatus.hasFailed()) {
             pindex->nStatus = pindex->nStatus.withFailedParent();
             setDirtyBlockIndex.insert(pindex);
         }
         if (pindex->IsValid(BlockValidity::TRANSACTIONS) &&
             (pindex->HaveTxsDownloaded() || pindex->pprev == nullptr)) {
             block_index_candidates.insert(pindex);
         }
 
         if (pindex->nStatus.isInvalid() &&
             (!pindexBestInvalid ||
              pindex->nChainWork > pindexBestInvalid->nChainWork)) {
             pindexBestInvalid = pindex;
         }
 
         if (pindex->nStatus.isOnParkedChain() &&
             (!pindexBestParked ||
              pindex->nChainWork > pindexBestParked->nChainWork)) {
             pindexBestParked = pindex;
         }
 
         if (pindex->pprev) {
             pindex->BuildSkip();
         }
 
         if (pindex->IsValid(BlockValidity::TREE) &&
             (pindexBestHeader == nullptr ||
              CBlockIndexWorkComparator()(pindexBestHeader, pindex))) {
             pindexBestHeader = pindex;
         }
     }
 
     return true;
 }
 
 void BlockManager::Unload() {
     m_failed_blocks.clear();
     m_blocks_unlinked.clear();
 
     for (const BlockMap::value_type &entry : m_block_index) {
         delete entry.second;
     }
 
     m_block_index.clear();
 }
 
 static bool LoadBlockIndexDB(ChainstateManager &chainman,
                              const Consensus::Params &params)
     EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
     if (!chainman.m_blockman.LoadBlockIndex(
             params, *pblocktree,
             ::ChainstateActive().setBlockIndexCandidates)) {
         return false;
     }
 
     // Load block file info
     pblocktree->ReadLastBlockFile(nLastBlockFile);
     vinfoBlockFile.resize(nLastBlockFile + 1);
     LogPrintf("%s: last block file = %i\n", __func__, nLastBlockFile);
     for (int nFile = 0; nFile <= nLastBlockFile; nFile++) {
         pblocktree->ReadBlockFileInfo(nFile, vinfoBlockFile[nFile]);
     }
     LogPrintf("%s: last block file info: %s\n", __func__,
               vinfoBlockFile[nLastBlockFile].ToString());
     for (int nFile = nLastBlockFile + 1; true; nFile++) {
         CBlockFileInfo info;
         if (pblocktree->ReadBlockFileInfo(nFile, info)) {
             vinfoBlockFile.push_back(info);
         } else {
             break;
         }
     }
 
     // Check presence of blk files
     LogPrintf("Checking all blk files are present...\n");
     std::set<int> setBlkDataFiles;
     for (const std::pair<const BlockHash, CBlockIndex *> &item :
          chainman.BlockIndex()) {
         CBlockIndex *pindex = item.second;
         if (pindex->nStatus.hasData()) {
             setBlkDataFiles.insert(pindex->nFile);
         }
     }
 
     for (const int i : setBlkDataFiles) {
         FlatFilePos pos(i, 0);
         if (CAutoFile(OpenBlockFile(pos, true), SER_DISK, CLIENT_VERSION)
                 .IsNull()) {
             return false;
         }
     }
 
     // Check whether we have ever pruned block & undo files
     pblocktree->ReadFlag("prunedblockfiles", fHavePruned);
     if (fHavePruned) {
         LogPrintf(
             "LoadBlockIndexDB(): Block files have previously been pruned\n");
     }
 
     // Check whether we need to continue reindexing
     if (pblocktree->IsReindexing()) {
         fReindex = true;
     }
 
     return true;
 }
 
 void CChainState::LoadMempool(const Config &config, const ArgsManager &args) {
     if (args.GetArg("-persistmempool", DEFAULT_PERSIST_MEMPOOL)) {
         ::LoadMempool(config, m_mempool);
     }
     m_mempool.SetIsLoaded(!ShutdownRequested());
 }
 
 bool CChainState::LoadChainTip(const CChainParams &chainparams) {
     AssertLockHeld(cs_main);
     const CCoinsViewCache &coins_cache = CoinsTip();
     // Never called when the coins view is empty
     assert(!coins_cache.GetBestBlock().IsNull());
     const CBlockIndex *tip = m_chain.Tip();
 
     if (tip && tip->GetBlockHash() == coins_cache.GetBestBlock()) {
         return true;
     }
 
     // Load pointer to end of best chain
     CBlockIndex *pindex = LookupBlockIndex(coins_cache.GetBestBlock());
     if (!pindex) {
         return false;
     }
     m_chain.SetTip(pindex);
     PruneBlockIndexCandidates();
 
     tip = m_chain.Tip();
     LogPrintf(
         "Loaded best chain: hashBestChain=%s height=%d date=%s progress=%f\n",
         tip->GetBlockHash().ToString(), m_chain.Height(),
         FormatISO8601DateTime(tip->GetBlockTime()),
         GuessVerificationProgress(chainparams.TxData(), tip));
     return true;
 }
 
 CVerifyDB::CVerifyDB() {
     uiInterface.ShowProgress(_("Verifying blocks...").translated, 0, false);
 }
 
 CVerifyDB::~CVerifyDB() {
     uiInterface.ShowProgress("", 100, false);
 }
 
 bool CVerifyDB::VerifyDB(const Config &config, CCoinsView *coinsview,
                          int nCheckLevel, int nCheckDepth) {
     LOCK(cs_main);
 
     const CChainParams &params = config.GetChainParams();
     const Consensus::Params &consensusParams = params.GetConsensus();
 
     if (::ChainActive().Tip() == nullptr ||
         ::ChainActive().Tip()->pprev == nullptr) {
         return true;
     }
 
     // Verify blocks in the best chain
     if (nCheckDepth <= 0 || nCheckDepth > ::ChainActive().Height()) {
         nCheckDepth = ::ChainActive().Height();
     }
 
     nCheckLevel = std::max(0, std::min(4, nCheckLevel));
     LogPrintf("Verifying last %i blocks at level %i\n", nCheckDepth,
               nCheckLevel);
 
     CCoinsViewCache coins(coinsview);
     CBlockIndex *pindex;
     CBlockIndex *pindexFailure = nullptr;
     int nGoodTransactions = 0;
     BlockValidationState state;
     int reportDone = 0;
     LogPrintfToBeContinued("[0%%]...");
     for (pindex = ::ChainActive().Tip(); pindex && pindex->pprev;
          pindex = pindex->pprev) {
         const int percentageDone =
             std::max(1, std::min(99, (int)(((double)(::ChainActive().Height() -
                                                      pindex->nHeight)) /
                                            (double)nCheckDepth *
                                            (nCheckLevel >= 4 ? 50 : 100))));
         if (reportDone < percentageDone / 10) {
             // report every 10% step
             LogPrintfToBeContinued("[%d%%]...", percentageDone);
             reportDone = percentageDone / 10;
         }
 
         uiInterface.ShowProgress(_("Verifying blocks...").translated,
                                  percentageDone, false);
         if (pindex->nHeight <= ::ChainActive().Height() - nCheckDepth) {
             break;
         }
 
         if (fPruneMode && !pindex->nStatus.hasData()) {
             // If pruning, only go back as far as we have data.
             LogPrintf("VerifyDB(): block verification stopping at height %d "
                       "(pruning, no data)\n",
                       pindex->nHeight);
             break;
         }
 
         CBlock block;
 
         // check level 0: read from disk
         if (!ReadBlockFromDisk(block, pindex, consensusParams)) {
             return error(
                 "VerifyDB(): *** ReadBlockFromDisk failed at %d, hash=%s",
                 pindex->nHeight, pindex->GetBlockHash().ToString());
         }
 
         // check level 1: verify block validity
         if (nCheckLevel >= 1 && !CheckBlock(block, state, consensusParams,
                                             BlockValidationOptions(config))) {
             return error("%s: *** found bad block at %d, hash=%s (%s)\n",
                          __func__, pindex->nHeight,
                          pindex->GetBlockHash().ToString(), state.ToString());
         }
 
         // check level 2: verify undo validity
         if (nCheckLevel >= 2 && pindex) {
             CBlockUndo undo;
             if (!pindex->GetUndoPos().IsNull()) {
                 if (!UndoReadFromDisk(undo, pindex)) {
                     return error(
                         "VerifyDB(): *** found bad undo data at %d, hash=%s\n",
                         pindex->nHeight, pindex->GetBlockHash().ToString());
                 }
             }
         }
         // check level 3: check for inconsistencies during memory-only
         // disconnect of tip blocks
         if (nCheckLevel >= 3 &&
             (coins.DynamicMemoryUsage() +
              ::ChainstateActive().CoinsTip().DynamicMemoryUsage()) <=
                 ::ChainstateActive().m_coinstip_cache_size_bytes) {
             assert(coins.GetBestBlock() == pindex->GetBlockHash());
             DisconnectResult res =
                 ::ChainstateActive().DisconnectBlock(block, pindex, coins);
             if (res == DisconnectResult::FAILED) {
                 return error("VerifyDB(): *** irrecoverable inconsistency in "
                              "block data at %d, hash=%s",
                              pindex->nHeight,
                              pindex->GetBlockHash().ToString());
             }
 
             if (res == DisconnectResult::UNCLEAN) {
                 nGoodTransactions = 0;
                 pindexFailure = pindex;
             } else {
                 nGoodTransactions += block.vtx.size();
             }
         }
 
         if (ShutdownRequested()) {
             return true;
         }
     }
 
     if (pindexFailure) {
         return error("VerifyDB(): *** coin database inconsistencies found "
                      "(last %i blocks, %i good transactions before that)\n",
                      ::ChainActive().Height() - pindexFailure->nHeight + 1,
                      nGoodTransactions);
     }
 
     // store block count as we move pindex at check level >= 4
     int block_count = ::ChainActive().Height() - pindex->nHeight;
 
     // check level 4: try reconnecting blocks
     if (nCheckLevel >= 4) {
         while (pindex != ::ChainActive().Tip()) {
             const int percentageDone = std::max(
                 1, std::min(99, 100 - int(double(::ChainActive().Height() -
                                                  pindex->nHeight) /
                                           double(nCheckDepth) * 50)));
             if (reportDone < percentageDone / 10) {
                 // report every 10% step
                 LogPrintfToBeContinued("[%d%%]...", percentageDone);
                 reportDone = percentageDone / 10;
             }
             uiInterface.ShowProgress(_("Verifying blocks...").translated,
                                      percentageDone, false);
             pindex = ::ChainActive().Next(pindex);
             CBlock block;
             if (!ReadBlockFromDisk(block, pindex, consensusParams)) {
                 return error(
                     "VerifyDB(): *** ReadBlockFromDisk failed at %d, hash=%s",
                     pindex->nHeight, pindex->GetBlockHash().ToString());
             }
             if (!::ChainstateActive().ConnectBlock(
                     block, state, pindex, coins, params,
                     BlockValidationOptions(config))) {
                 return error("VerifyDB(): *** found unconnectable block at %d, "
                              "hash=%s (%s)",
                              pindex->nHeight, pindex->GetBlockHash().ToString(),
                              state.ToString());
             }
             if (ShutdownRequested()) {
                 return true;
             }
         }
     }
 
     LogPrintf("[DONE].\n");
     LogPrintf("No coin database inconsistencies in last %i blocks (%i "
               "transactions)\n",
               block_count, nGoodTransactions);
 
     return true;
 }
 
 /**
  * Apply the effects of a block on the utxo cache, ignoring that it may already
  * have been applied.
  */
 bool CChainState::RollforwardBlock(const CBlockIndex *pindex,
                                    CCoinsViewCache &view,
                                    const Consensus::Params &params) {
     // TODO: merge with ConnectBlock
     CBlock block;
     if (!ReadBlockFromDisk(block, pindex, params)) {
         return error("ReplayBlock(): ReadBlockFromDisk failed at %d, hash=%s",
                      pindex->nHeight, pindex->GetBlockHash().ToString());
     }
 
     for (const CTransactionRef &tx : block.vtx) {
         // Pass check = true as every addition may be an overwrite.
         AddCoins(view, *tx, pindex->nHeight, true);
     }
 
     for (const CTransactionRef &tx : block.vtx) {
         if (tx->IsCoinBase()) {
             continue;
         }
 
         for (const CTxIn &txin : tx->vin) {
             view.SpendCoin(txin.prevout);
         }
     }
 
     return true;
 }
 
 bool CChainState::ReplayBlocks(const Consensus::Params &params) {
     LOCK(cs_main);
 
     CCoinsView &db = this->CoinsDB();
     CCoinsViewCache cache(&db);
 
     std::vector<BlockHash> hashHeads = db.GetHeadBlocks();
     if (hashHeads.empty()) {
         // We're already in a consistent state.
         return true;
     }
     if (hashHeads.size() != 2) {
         return error("ReplayBlocks(): unknown inconsistent state");
     }
 
     uiInterface.ShowProgress(_("Replaying blocks...").translated, 0, false);
     LogPrintf("Replaying blocks\n");
 
     // Old tip during the interrupted flush.
     const CBlockIndex *pindexOld = nullptr;
     // New tip during the interrupted flush.
     const CBlockIndex *pindexNew;
     // Latest block common to both the old and the new tip.
     const CBlockIndex *pindexFork = nullptr;
 
     if (m_blockman.m_block_index.count(hashHeads[0]) == 0) {
         return error(
             "ReplayBlocks(): reorganization to unknown block requested");
     }
 
     pindexNew = m_blockman.m_block_index[hashHeads[0]];
 
     if (!hashHeads[1].IsNull()) {
         // The old tip is allowed to be 0, indicating it's the first flush.
         if (m_blockman.m_block_index.count(hashHeads[1]) == 0) {
             return error(
                 "ReplayBlocks(): reorganization from unknown block requested");
         }
 
         pindexOld = m_blockman.m_block_index[hashHeads[1]];
         pindexFork = LastCommonAncestor(pindexOld, pindexNew);
         assert(pindexFork != nullptr);
     }
 
     // Rollback along the old branch.
     while (pindexOld != pindexFork) {
         if (pindexOld->nHeight > 0) {
             // Never disconnect the genesis block.
             CBlock block;
             if (!ReadBlockFromDisk(block, pindexOld, params)) {
                 return error("RollbackBlock(): ReadBlockFromDisk() failed at "
                              "%d, hash=%s",
                              pindexOld->nHeight,
                              pindexOld->GetBlockHash().ToString());
             }
 
             LogPrintf("Rolling back %s (%i)\n",
                       pindexOld->GetBlockHash().ToString(), pindexOld->nHeight);
             DisconnectResult res = DisconnectBlock(block, pindexOld, cache);
             if (res == DisconnectResult::FAILED) {
                 return error(
                     "RollbackBlock(): DisconnectBlock failed at %d, hash=%s",
                     pindexOld->nHeight, pindexOld->GetBlockHash().ToString());
             }
 
             // If DisconnectResult::UNCLEAN is returned, it means a non-existing
             // UTXO was deleted, or an existing UTXO was overwritten. It
             // corresponds to cases where the block-to-be-disconnect never had
             // all its operations applied to the UTXO set. However, as both
             // writing a UTXO and deleting a UTXO are idempotent operations, the
             // result is still a version of the UTXO set with the effects of
             // that block undone.
         }
         pindexOld = pindexOld->pprev;
     }
 
     // Roll forward from the forking point to the new tip.
     int nForkHeight = pindexFork ? pindexFork->nHeight : 0;
     for (int nHeight = nForkHeight + 1; nHeight <= pindexNew->nHeight;
          ++nHeight) {
         const CBlockIndex *pindex = pindexNew->GetAncestor(nHeight);
         LogPrintf("Rolling forward %s (%i)\n",
                   pindex->GetBlockHash().ToString(), nHeight);
         uiInterface.ShowProgress(_("Replaying blocks...").translated,
                                  (int)((nHeight - nForkHeight) * 100.0 /
                                        (pindexNew->nHeight - nForkHeight)),
                                  false);
         if (!RollforwardBlock(pindex, cache, params)) {
             return false;
         }
     }
 
     cache.SetBestBlock(pindexNew->GetBlockHash());
     cache.Flush();
     uiInterface.ShowProgress("", 100, false);
     return true;
 }
 
 // May NOT be used after any connections are up as much of the peer-processing
 // logic assumes a consistent block index state
 void CChainState::UnloadBlockIndex() {
     nBlockSequenceId = 1;
     setBlockIndexCandidates.clear();
 
     // Do not point to CBlockIndex that will be free'd
     m_finalizedBlockIndex = nullptr;
 }
 
 // May NOT be used after any connections are up as much
 // of the peer-processing logic assumes a consistent
 // block index state
 void UnloadBlockIndex(CTxMemPool *mempool, ChainstateManager &chainman) {
     LOCK(cs_main);
     chainman.Unload();
     pindexBestInvalid = nullptr;
     pindexBestParked = nullptr;
     pindexBestHeader = nullptr;
     pindexBestForkTip = nullptr;
     pindexBestForkBase = nullptr;
     ResetASERTAnchorBlockCache();
     if (mempool) {
         mempool->clear();
     }
     vinfoBlockFile.clear();
     nLastBlockFile = 0;
     setDirtyBlockIndex.clear();
     setDirtyFileInfo.clear();
     fHavePruned = false;
 }
 
 bool ChainstateManager::LoadBlockIndex(const Consensus::Params &params) {
     AssertLockHeld(cs_main);
     // Load block index from databases
     bool needs_init = fReindex;
     if (!fReindex) {
         bool ret = LoadBlockIndexDB(*this, params);
         if (!ret) {
             return false;
         }
 
         needs_init = m_blockman.m_block_index.empty();
     }
 
     if (needs_init) {
         // Everything here is for *new* reindex/DBs. Thus, though
         // LoadBlockIndexDB may have set fReindex if we shut down
         // mid-reindex previously, we don't check fReindex and
         // instead only check it prior to LoadBlockIndexDB to set
         // needs_init.
 
         LogPrintf("Initializing databases...\n");
     }
     return true;
 }
 
 bool CChainState::LoadGenesisBlock(const CChainParams &chainparams) {
     LOCK(cs_main);
 
     // Check whether we're already initialized by checking for genesis in
     // m_blockman.m_block_index. Note that we can't use m_chain here, since it
     // is set based on the coins db, not the block index db, which is the only
     // thing loaded at this point.
     if (m_blockman.m_block_index.count(chainparams.GenesisBlock().GetHash())) {
         return true;
     }
 
     try {
         const CBlock &block = chainparams.GenesisBlock();
         FlatFilePos blockPos = SaveBlockToDisk(block, 0, chainparams, nullptr);
         if (blockPos.IsNull()) {
             return error("%s: writing genesis block to disk failed", __func__);
         }
         CBlockIndex *pindex = m_blockman.AddToBlockIndex(block);
         ReceivedBlockTransactions(block, pindex, blockPos);
     } catch (const std::runtime_error &e) {
         return error("%s: failed to write genesis block: %s", __func__,
                      e.what());
     }
 
     return true;
 }
 
 bool LoadGenesisBlock(const CChainParams &chainparams) {
     return ::ChainstateActive().LoadGenesisBlock(chainparams);
 }
 
 void LoadExternalBlockFile(const Config &config, FILE *fileIn,
                            FlatFilePos *dbp) {
     // Map of disk positions for blocks with unknown parent (only used for
     // reindex)
     static std::multimap<uint256, FlatFilePos> mapBlocksUnknownParent;
     int64_t nStart = GetTimeMillis();
 
     const CChainParams &chainparams = config.GetChainParams();
 
     int nLoaded = 0;
     try {
         // This takes over fileIn and calls fclose() on it in the CBufferedFile
         // destructor. Make sure we have at least 2*MAX_TX_SIZE space in there
         // so any transaction can fit in the buffer.
         CBufferedFile blkdat(fileIn, 2 * MAX_TX_SIZE, MAX_TX_SIZE + 8, SER_DISK,
                              CLIENT_VERSION);
         uint64_t nRewind = blkdat.GetPos();
         while (!blkdat.eof()) {
             if (ShutdownRequested()) {
                 return;
             }
 
             blkdat.SetPos(nRewind);
             // Start one byte further next time, in case of failure.
             nRewind++;
             // Remove former limit.
             blkdat.SetLimit();
             unsigned int nSize = 0;
             try {
                 // Locate a header.
                 uint8_t buf[CMessageHeader::MESSAGE_START_SIZE];
                 blkdat.FindByte(chainparams.DiskMagic()[0]);
                 nRewind = blkdat.GetPos() + 1;
                 blkdat >> buf;
                 if (memcmp(buf, chainparams.DiskMagic().data(),
                            CMessageHeader::MESSAGE_START_SIZE)) {
                     continue;
                 }
 
                 // Read size.
                 blkdat >> nSize;
                 if (nSize < 80) {
                     continue;
                 }
             } catch (const std::exception &) {
                 // No valid block header found; don't complain.
                 break;
             }
 
             try {
                 // read block
                 uint64_t nBlockPos = blkdat.GetPos();
                 if (dbp) {
                     dbp->nPos = nBlockPos;
                 }
                 blkdat.SetLimit(nBlockPos + nSize);
                 std::shared_ptr<CBlock> pblock = std::make_shared<CBlock>();
                 CBlock &block = *pblock;
                 blkdat >> block;
                 nRewind = blkdat.GetPos();
 
                 const BlockHash hash = block.GetHash();
                 {
                     LOCK(cs_main);
                     // detect out of order blocks, and store them for later
                     if (hash != chainparams.GetConsensus().hashGenesisBlock &&
                         !LookupBlockIndex(block.hashPrevBlock)) {
                         LogPrint(
                             BCLog::REINDEX,
                             "%s: Out of order block %s, parent %s not known\n",
                             __func__, hash.ToString(),
                             block.hashPrevBlock.ToString());
                         if (dbp) {
                             mapBlocksUnknownParent.insert(
                                 std::make_pair(block.hashPrevBlock, *dbp));
                         }
                         continue;
                     }
 
                     // process in case the block isn't known yet
                     CBlockIndex *pindex = LookupBlockIndex(hash);
                     if (!pindex || !pindex->nStatus.hasData()) {
                         BlockValidationState state;
                         if (::ChainstateActive().AcceptBlock(
                                 config, pblock, state, true, dbp, nullptr)) {
                             nLoaded++;
                         }
                         if (state.IsError()) {
                             break;
                         }
                     } else if (hash != chainparams.GetConsensus()
                                            .hashGenesisBlock &&
                                pindex->nHeight % 1000 == 0) {
                         LogPrint(
                             BCLog::REINDEX,
                             "Block Import: already had block %s at height %d\n",
                             hash.ToString(), pindex->nHeight);
                     }
                 }
 
                 // Activate the genesis block so normal node progress can
                 // continue
                 if (hash == chainparams.GetConsensus().hashGenesisBlock) {
                     BlockValidationState state;
                     if (!ActivateBestChain(config, state, nullptr)) {
                         break;
                     }
                 }
 
                 NotifyHeaderTip();
 
                 // Recursively process earlier encountered successors of this
                 // block
                 std::deque<uint256> queue;
                 queue.push_back(hash);
                 while (!queue.empty()) {
                     uint256 head = queue.front();
                     queue.pop_front();
                     std::pair<std::multimap<uint256, FlatFilePos>::iterator,
                               std::multimap<uint256, FlatFilePos>::iterator>
                         range = mapBlocksUnknownParent.equal_range(head);
                     while (range.first != range.second) {
                         std::multimap<uint256, FlatFilePos>::iterator it =
                             range.first;
                         std::shared_ptr<CBlock> pblockrecursive =
                             std::make_shared<CBlock>();
                         if (ReadBlockFromDisk(*pblockrecursive, it->second,
                                               chainparams.GetConsensus())) {
                             LogPrint(
                                 BCLog::REINDEX,
                                 "%s: Processing out of order child %s of %s\n",
                                 __func__, pblockrecursive->GetHash().ToString(),
                                 head.ToString());
                             LOCK(cs_main);
                             BlockValidationState dummy;
                             if (::ChainstateActive().AcceptBlock(
                                     config, pblockrecursive, dummy, true,
                                     &it->second, nullptr)) {
                                 nLoaded++;
                                 queue.push_back(pblockrecursive->GetHash());
                             }
                         }
                         range.first++;
                         mapBlocksUnknownParent.erase(it);
                         NotifyHeaderTip();
                     }
                 }
             } catch (const std::exception &e) {
                 LogPrintf("%s: Deserialize or I/O error - %s\n", __func__,
                           e.what());
             }
         }
     } catch (const std::runtime_error &e) {
         AbortNode(std::string("System error: ") + e.what());
     }
 
     LogPrintf("Loaded %i blocks from external file in %dms\n", nLoaded,
               GetTimeMillis() - nStart);
 }
 
 void CChainState::CheckBlockIndex(const Consensus::Params &consensusParams) {
     if (!fCheckBlockIndex) {
         return;
     }
 
     LOCK(cs_main);
 
     // During a reindex, we read the genesis block and call CheckBlockIndex
     // before ActivateBestChain, so we have the genesis block in
     // m_blockman.m_block_index but no active chain. (A few of the tests when
     // iterating the block tree require that m_chain has been initialized.)
     if (m_chain.Height() < 0) {
         assert(m_blockman.m_block_index.size() <= 1);
         return;
     }
 
     // Build forward-pointing map of the entire block tree.
     std::multimap<CBlockIndex *, CBlockIndex *> forward;
     for (const auto &entry : m_blockman.m_block_index) {
         forward.emplace(entry.second->pprev, entry.second);
     }
 
     assert(forward.size() == m_blockman.m_block_index.size());
 
     std::pair<std::multimap<CBlockIndex *, CBlockIndex *>::iterator,
               std::multimap<CBlockIndex *, CBlockIndex *>::iterator>
         rangeGenesis = forward.equal_range(nullptr);
     CBlockIndex *pindex = rangeGenesis.first->second;
     rangeGenesis.first++;
     // There is only one index entry with parent nullptr.
     assert(rangeGenesis.first == rangeGenesis.second);
 
     // Iterate over the entire block tree, using depth-first search.
     // Along the way, remember whether there are blocks on the path from genesis
     // block being explored which are the first to have certain properties.
     size_t nNodes = 0;
     int nHeight = 0;
     // Oldest ancestor of pindex which is invalid.
     CBlockIndex *pindexFirstInvalid = nullptr;
     // Oldest ancestor of pindex which is parked.
     CBlockIndex *pindexFirstParked = nullptr;
     // Oldest ancestor of pindex which does not have data available.
     CBlockIndex *pindexFirstMissing = nullptr;
     // Oldest ancestor of pindex for which nTx == 0.
     CBlockIndex *pindexFirstNeverProcessed = nullptr;
     // Oldest ancestor of pindex which does not have BLOCK_VALID_TREE
     // (regardless of being valid or not).
     CBlockIndex *pindexFirstNotTreeValid = nullptr;
     // Oldest ancestor of pindex which does not have BLOCK_VALID_TRANSACTIONS
     // (regardless of being valid or not).
     CBlockIndex *pindexFirstNotTransactionsValid = nullptr;
     // Oldest ancestor of pindex which does not have BLOCK_VALID_CHAIN
     // (regardless of being valid or not).
     CBlockIndex *pindexFirstNotChainValid = nullptr;
     // Oldest ancestor of pindex which does not have BLOCK_VALID_SCRIPTS
     // (regardless of being valid or not).
     CBlockIndex *pindexFirstNotScriptsValid = nullptr;
     while (pindex != nullptr) {
         nNodes++;
         if (pindexFirstInvalid == nullptr && pindex->nStatus.hasFailed()) {
             pindexFirstInvalid = pindex;
         }
         if (pindexFirstParked == nullptr && pindex->nStatus.isParked()) {
             pindexFirstParked = pindex;
         }
         if (pindexFirstMissing == nullptr && !pindex->nStatus.hasData()) {
             pindexFirstMissing = pindex;
         }
         if (pindexFirstNeverProcessed == nullptr && pindex->nTx == 0) {
             pindexFirstNeverProcessed = pindex;
         }
         if (pindex->pprev != nullptr && pindexFirstNotTreeValid == nullptr &&
             pindex->nStatus.getValidity() < BlockValidity::TREE) {
             pindexFirstNotTreeValid = pindex;
         }
         if (pindex->pprev != nullptr &&
             pindexFirstNotTransactionsValid == nullptr &&
             pindex->nStatus.getValidity() < BlockValidity::TRANSACTIONS) {
             pindexFirstNotTransactionsValid = pindex;
         }
         if (pindex->pprev != nullptr && pindexFirstNotChainValid == nullptr &&
             pindex->nStatus.getValidity() < BlockValidity::CHAIN) {
             pindexFirstNotChainValid = pindex;
         }
         if (pindex->pprev != nullptr && pindexFirstNotScriptsValid == nullptr &&
             pindex->nStatus.getValidity() < BlockValidity::SCRIPTS) {
             pindexFirstNotScriptsValid = pindex;
         }
 
         // Begin: actual consistency checks.
         if (pindex->pprev == nullptr) {
             // Genesis block checks.
             // Genesis block's hash must match.
             assert(pindex->GetBlockHash() == consensusParams.hashGenesisBlock);
             // The current active chain's genesis block must be this block.
             assert(pindex == m_chain.Genesis());
         }
         if (!pindex->HaveTxsDownloaded()) {
             // nSequenceId can't be set positive for blocks that aren't linked
             // (negative is used for preciousblock)
             assert(pindex->nSequenceId <= 0);
         }
         // VALID_TRANSACTIONS is equivalent to nTx > 0 for all nodes (whether or
         // not pruning has occurred). HAVE_DATA is only equivalent to nTx > 0
         // (or VALID_TRANSACTIONS) if no pruning has occurred.
         if (!fHavePruned) {
             // If we've never pruned, then HAVE_DATA should be equivalent to nTx
             // > 0
             assert(pindex->nStatus.hasData() == (pindex->nTx > 0));
             assert(pindexFirstMissing == pindexFirstNeverProcessed);
         } else if (pindex->nStatus.hasData()) {
             // If we have pruned, then we can only say that HAVE_DATA implies
             // nTx > 0
             assert(pindex->nTx > 0);
         }
         if (pindex->nStatus.hasUndo()) {
             assert(pindex->nStatus.hasData());
         }
         // This is pruning-independent.
         assert((pindex->nStatus.getValidity() >= BlockValidity::TRANSACTIONS) ==
                (pindex->nTx > 0));
         // All parents having had data (at some point) is equivalent to all
         // parents being VALID_TRANSACTIONS, which is equivalent to
         // HaveTxsDownloaded(). All parents having had data (at some point) is
         // equivalent to all parents being VALID_TRANSACTIONS, which is
         // equivalent to HaveTxsDownloaded().
         assert((pindexFirstNeverProcessed == nullptr) ==
                (pindex->HaveTxsDownloaded()));
         assert((pindexFirstNotTransactionsValid == nullptr) ==
                (pindex->HaveTxsDownloaded()));
         // nHeight must be consistent.
         assert(pindex->nHeight == nHeight);
         // For every block except the genesis block, the chainwork must be
         // larger than the parent's.
         assert(pindex->pprev == nullptr ||
                pindex->nChainWork >= pindex->pprev->nChainWork);
         // The pskip pointer must point back for all but the first 2 blocks.
         assert(nHeight < 2 ||
                (pindex->pskip && (pindex->pskip->nHeight < nHeight)));
         // All m_blockman.m_block_index entries must at least be TREE valid
         assert(pindexFirstNotTreeValid == nullptr);
         if (pindex->nStatus.getValidity() >= BlockValidity::TREE) {
             // TREE valid implies all parents are TREE valid
             assert(pindexFirstNotTreeValid == nullptr);
         }
         if (pindex->nStatus.getValidity() >= BlockValidity::CHAIN) {
             // CHAIN valid implies all parents are CHAIN valid
             assert(pindexFirstNotChainValid == nullptr);
         }
         if (pindex->nStatus.getValidity() >= BlockValidity::SCRIPTS) {
             // SCRIPTS valid implies all parents are SCRIPTS valid
             assert(pindexFirstNotScriptsValid == nullptr);
         }
         if (pindexFirstInvalid == nullptr) {
             // Checks for not-invalid blocks.
             // The failed mask cannot be set for blocks without invalid parents.
             assert(!pindex->nStatus.isInvalid());
         }
         if (pindexFirstParked == nullptr) {
             // Checks for not-parked blocks.
             // The parked mask cannot be set for blocks without parked parents.
             // (i.e., hasParkedParent only if an ancestor is properly parked).
             assert(!pindex->nStatus.isOnParkedChain());
         }
         if (!CBlockIndexWorkComparator()(pindex, m_chain.Tip()) &&
             pindexFirstNeverProcessed == nullptr) {
             if (pindexFirstInvalid == nullptr) {
                 // If this block sorts at least as good as the current tip and
                 // is valid and we have all data for its parents, it must be in
                 // setBlockIndexCandidates or be parked.
                 if (pindexFirstMissing == nullptr) {
                     assert(pindex->nStatus.isOnParkedChain() ||
                            setBlockIndexCandidates.count(pindex));
                 }
                 // m_chain.Tip() must also be there even if some data has
                 // been pruned.
                 if (pindex == m_chain.Tip()) {
                     assert(setBlockIndexCandidates.count(pindex));
                 }
                 // If some parent is missing, then it could be that this block
                 // was in setBlockIndexCandidates but had to be removed because
                 // of the missing data. In this case it must be in
                 // m_blocks_unlinked -- see test below.
             }
         } else {
             // If this block sorts worse than the current tip or some ancestor's
             // block has never been seen, it cannot be in
             // setBlockIndexCandidates.
             assert(setBlockIndexCandidates.count(pindex) == 0);
         }
         // Check whether this block is in m_blocks_unlinked.
         std::pair<std::multimap<CBlockIndex *, CBlockIndex *>::iterator,
                   std::multimap<CBlockIndex *, CBlockIndex *>::iterator>
             rangeUnlinked =
                 m_blockman.m_blocks_unlinked.equal_range(pindex->pprev);
         bool foundInUnlinked = false;
         while (rangeUnlinked.first != rangeUnlinked.second) {
             assert(rangeUnlinked.first->first == pindex->pprev);
             if (rangeUnlinked.first->second == pindex) {
                 foundInUnlinked = true;
                 break;
             }
             rangeUnlinked.first++;
         }
         if (pindex->pprev && pindex->nStatus.hasData() &&
             pindexFirstNeverProcessed != nullptr &&
             pindexFirstInvalid == nullptr) {
             // If this block has block data available, some parent was never
             // received, and has no invalid parents, it must be in
             // m_blocks_unlinked.
             assert(foundInUnlinked);
         }
         if (!pindex->nStatus.hasData()) {
             // Can't be in m_blocks_unlinked if we don't HAVE_DATA
             assert(!foundInUnlinked);
         }
         if (pindexFirstMissing == nullptr) {
             // We aren't missing data for any parent -- cannot be in
             // m_blocks_unlinked.
             assert(!foundInUnlinked);
         }
         if (pindex->pprev && pindex->nStatus.hasData() &&
             pindexFirstNeverProcessed == nullptr &&
             pindexFirstMissing != nullptr) {
             // We HAVE_DATA for this block, have received data for all parents
             // at some point, but we're currently missing data for some parent.
             // We must have pruned.
             assert(fHavePruned);
             // This block may have entered m_blocks_unlinked if:
             //  - it has a descendant that at some point had more work than the
             //    tip, and
             //  - we tried switching to that descendant but were missing
             //    data for some intermediate block between m_chain and the
             //    tip.
             // So if this block is itself better than m_chain.Tip() and it
             // wasn't in
             // setBlockIndexCandidates, then it must be in m_blocks_unlinked.
             if (!CBlockIndexWorkComparator()(pindex, m_chain.Tip()) &&
                 setBlockIndexCandidates.count(pindex) == 0) {
                 if (pindexFirstInvalid == nullptr) {
                     assert(foundInUnlinked);
                 }
             }
         }
         // Perhaps too slow
         // assert(pindex->GetBlockHash() == pindex->GetBlockHeader().GetHash());
         // End: actual consistency checks.
 
         // Try descending into the first subnode.
         std::pair<std::multimap<CBlockIndex *, CBlockIndex *>::iterator,
                   std::multimap<CBlockIndex *, CBlockIndex *>::iterator>
             range = forward.equal_range(pindex);
         if (range.first != range.second) {
             // A subnode was found.
             pindex = range.first->second;
             nHeight++;
             continue;
         }
         // This is a leaf node. Move upwards until we reach a node of which we
         // have not yet visited the last child.
         while (pindex) {
             // We are going to either move to a parent or a sibling of pindex.
             // If pindex was the first with a certain property, unset the
             // corresponding variable.
             if (pindex == pindexFirstInvalid) {
                 pindexFirstInvalid = nullptr;
             }
             if (pindex == pindexFirstParked) {
                 pindexFirstParked = nullptr;
             }
             if (pindex == pindexFirstMissing) {
                 pindexFirstMissing = nullptr;
             }
             if (pindex == pindexFirstNeverProcessed) {
                 pindexFirstNeverProcessed = nullptr;
             }
             if (pindex == pindexFirstNotTreeValid) {
                 pindexFirstNotTreeValid = nullptr;
             }
             if (pindex == pindexFirstNotTransactionsValid) {
                 pindexFirstNotTransactionsValid = nullptr;
             }
             if (pindex == pindexFirstNotChainValid) {
                 pindexFirstNotChainValid = nullptr;
             }
             if (pindex == pindexFirstNotScriptsValid) {
                 pindexFirstNotScriptsValid = nullptr;
             }
             // Find our parent.
             CBlockIndex *pindexPar = pindex->pprev;
             // Find which child we just visited.
             std::pair<std::multimap<CBlockIndex *, CBlockIndex *>::iterator,
                       std::multimap<CBlockIndex *, CBlockIndex *>::iterator>
                 rangePar = forward.equal_range(pindexPar);
             while (rangePar.first->second != pindex) {
                 // Our parent must have at least the node we're coming from as
                 // child.
                 assert(rangePar.first != rangePar.second);
                 rangePar.first++;
             }
             // Proceed to the next one.
             rangePar.first++;
             if (rangePar.first != rangePar.second) {
                 // Move to the sibling.
                 pindex = rangePar.first->second;
                 break;
             } else {
                 // Move up further.
                 pindex = pindexPar;
                 nHeight--;
                 continue;
             }
         }
     }
 
     // Check that we actually traversed the entire map.
     assert(nNodes == forward.size());
 }
 
 std::string CChainState::ToString() {
     CBlockIndex *tip = m_chain.Tip();
     return strprintf("Chainstate [%s] @ height %d (%s)",
                      m_from_snapshot_blockhash.IsNull() ? "ibd" : "snapshot",
                      tip ? tip->nHeight : -1,
                      tip ? tip->GetBlockHash().ToString() : "null");
 }
 
 bool CChainState::ResizeCoinsCaches(size_t coinstip_size, size_t coinsdb_size) {
     if (coinstip_size == m_coinstip_cache_size_bytes &&
         coinsdb_size == m_coinsdb_cache_size_bytes) {
         // Cache sizes are unchanged, no need to continue.
         return true;
     }
     size_t old_coinstip_size = m_coinstip_cache_size_bytes;
     m_coinstip_cache_size_bytes = coinstip_size;
     m_coinsdb_cache_size_bytes = coinsdb_size;
     CoinsDB().ResizeCache(coinsdb_size);
 
     LogPrintf("[%s] resized coinsdb cache to %.1f MiB\n", this->ToString(),
               coinsdb_size * (1.0 / 1024 / 1024));
     LogPrintf("[%s] resized coinstip cache to %.1f MiB\n", this->ToString(),
               coinstip_size * (1.0 / 1024 / 1024));
 
     BlockValidationState state;
     const CChainParams &chainparams = Params();
 
     bool ret;
 
     if (coinstip_size > old_coinstip_size) {
         // Likely no need to flush if cache sizes have grown.
         ret = FlushStateToDisk(chainparams, state, FlushStateMode::IF_NEEDED);
     } else {
         // Otherwise, flush state to disk and deallocate the in-memory coins
         // map.
         ret = FlushStateToDisk(chainparams, state, FlushStateMode::ALWAYS);
         CoinsTip().ReallocateCache();
     }
     return ret;
 }
 
 std::string CBlockFileInfo::ToString() const {
     return strprintf(
         "CBlockFileInfo(blocks=%u, size=%u, heights=%u...%u, time=%s...%s)",
         nBlocks, nSize, nHeightFirst, nHeightLast,
         FormatISO8601DateTime(nTimeFirst), FormatISO8601DateTime(nTimeLast));
 }
 
 CBlockFileInfo *GetBlockFileInfo(size_t n) {
     LOCK(cs_LastBlockFile);
 
     return &vinfoBlockFile.at(n);
 }
 
 static ThresholdState VersionBitsStateImpl(const Consensus::Params &params,
                                            Consensus::DeploymentPos pos,
                                            const CBlockIndex *pindex)
     EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
     return VersionBitsState(pindex, params, pos, versionbitscache);
 }
 
 ThresholdState VersionBitsTipState(const Consensus::Params &params,
                                    Consensus::DeploymentPos pos) {
     LOCK(cs_main);
     return VersionBitsStateImpl(params, pos, ::ChainActive().Tip());
 }
 
 ThresholdState VersionBitsBlockState(const Consensus::Params &params,
                                      Consensus::DeploymentPos pos,
                                      const CBlockIndex *pindex) {
     LOCK(cs_main);
     return VersionBitsStateImpl(params, pos, pindex);
 }
 
 BIP9Stats VersionBitsTipStatistics(const Consensus::Params &params,
                                    Consensus::DeploymentPos pos) {
     LOCK(cs_main);
     return VersionBitsStatistics(::ChainActive().Tip(), params, pos);
 }
 
 int VersionBitsTipStateSinceHeight(const Consensus::Params &params,
                                    Consensus::DeploymentPos pos) {
     LOCK(cs_main);
     return VersionBitsStateSinceHeight(::ChainActive().Tip(), params, pos,
                                        versionbitscache);
 }
 
 static const uint64_t MEMPOOL_DUMP_VERSION = 1;
 
 bool LoadMempool(const Config &config, CTxMemPool &pool) {
     int64_t nExpiryTimeout =
         gArgs.GetArg("-mempoolexpiry", DEFAULT_MEMPOOL_EXPIRY) * 60 * 60;
     FILE *filestr = fsbridge::fopen(GetDataDir() / "mempool.dat", "rb");
     CAutoFile file(filestr, SER_DISK, CLIENT_VERSION);
     if (file.IsNull()) {
         LogPrintf(
             "Failed to open mempool file from disk. Continuing anyway.\n");
         return false;
     }
 
     int64_t count = 0;
     int64_t expired = 0;
     int64_t failed = 0;
     int64_t already_there = 0;
     int64_t unbroadcast = 0;
     int64_t nNow = GetTime();
 
     try {
         uint64_t version;
         file >> version;
         if (version != MEMPOOL_DUMP_VERSION) {
             return false;
         }
 
         uint64_t num;
         file >> num;
         while (num--) {
             CTransactionRef tx;
             int64_t nTime;
             int64_t nFeeDelta;
             file >> tx;
             file >> nTime;
             file >> nFeeDelta;
 
             Amount amountdelta = nFeeDelta * SATOSHI;
             if (amountdelta != Amount::zero()) {
                 pool.PrioritiseTransaction(tx->GetId(), amountdelta);
             }
             TxValidationState state;
             if (nTime + nExpiryTimeout > nNow) {
                 LOCK(cs_main);
                 AcceptToMemoryPoolWithTime(
                     config, pool, state, tx, nTime, false /* bypass_limits */,
                     Amount::zero() /* nAbsurdFee */, false /* test_accept */);
                 if (state.IsValid()) {
                     ++count;
                 } else {
                     // mempool may contain the transaction already, e.g. from
                     // wallet(s) having loaded it while we were processing
                     // mempool transactions; consider these as valid, instead of
                     // failed, but mark them as 'already there'
                     if (pool.exists(tx->GetId())) {
                         ++already_there;
                     } else {
                         ++failed;
                     }
                 }
             } else {
                 ++expired;
             }
 
             if (ShutdownRequested()) {
                 return false;
             }
         }
         std::map<TxId, Amount> mapDeltas;
         file >> mapDeltas;
 
         for (const auto &i : mapDeltas) {
             pool.PrioritiseTransaction(i.first, i.second);
         }
 
         // TODO: remove this try...catch after May 15th 2021,
         // when no one is running v0.22.11 or lower anymore.
         // This will be done by backporting PR20854.
         try {
             std::set<TxId> unbroadcast_txids;
             file >> unbroadcast_txids;
             unbroadcast = unbroadcast_txids.size();
             for (const auto &txid : unbroadcast_txids) {
                 pool.AddUnbroadcastTx(txid);
             }
         } catch (const std::exception &) {
             // mempool.dat files created prior to v0.22.12 will not have an
             // unbroadcast set. No need to log a failure if parsing fails here.
         }
 
     } catch (const std::exception &e) {
         LogPrintf("Failed to deserialize mempool data on disk: %s. Continuing "
                   "anyway.\n",
                   e.what());
         return false;
     }
 
     LogPrintf("Imported mempool transactions from disk: %i succeeded, %i "
               "failed, %i expired, %i already there, %i waiting for initial "
               "broadcast\n",
               count, failed, expired, already_there, unbroadcast);
     return true;
 }
 
 bool DumpMempool(const CTxMemPool &pool) {
     int64_t start = GetTimeMicros();
 
     std::map<uint256, Amount> mapDeltas;
     std::vector<TxMempoolInfo> vinfo;
     std::set<TxId> unbroadcast_txids;
 
     static Mutex dump_mutex;
     LOCK(dump_mutex);
 
     {
         LOCK(pool.cs);
         for (const auto &i : pool.mapDeltas) {
             mapDeltas[i.first] = i.second;
         }
 
         vinfo = pool.infoAll();
         unbroadcast_txids = pool.GetUnbroadcastTxs();
     }
 
     int64_t mid = GetTimeMicros();
 
     try {
         FILE *filestr = fsbridge::fopen(GetDataDir() / "mempool.dat.new", "wb");
         if (!filestr) {
             return false;
         }
 
         CAutoFile file(filestr, SER_DISK, CLIENT_VERSION);
 
         uint64_t version = MEMPOOL_DUMP_VERSION;
         file << version;
 
         file << uint64_t(vinfo.size());
         for (const auto &i : vinfo) {
             file << *(i.tx);
             file << int64_t(count_seconds(i.m_time));
             file << i.nFeeDelta;
             mapDeltas.erase(i.tx->GetId());
         }
 
         file << mapDeltas;
 
         LogPrintf("Writing %d unbroadcast transactions to disk.\n",
                   unbroadcast_txids.size());
         file << unbroadcast_txids;
 
         if (!FileCommit(file.Get())) {
             throw std::runtime_error("FileCommit failed");
         }
         file.fclose();
         RenameOver(GetDataDir() / "mempool.dat.new",
                    GetDataDir() / "mempool.dat");
         int64_t last = GetTimeMicros();
         LogPrintf("Dumped mempool: %gs to copy, %gs to dump\n",
                   (mid - start) * MICRO, (last - mid) * MICRO);
     } catch (const std::exception &e) {
         LogPrintf("Failed to dump mempool: %s. Continuing anyway.\n", e.what());
         return false;
     }
     return true;
 }
 
 bool IsBlockPruned(const CBlockIndex *pblockindex) {
     return (fHavePruned && !pblockindex->nStatus.hasData() &&
             pblockindex->nTx > 0);
 }
 
 //! Guess how far we are in the verification process at the given block index
 //! require cs_main if pindex has not been validated yet (because the chain's
 //! transaction count might be unset) This conditional lock requirement might be
 //! confusing, see: https://github.com/bitcoin/bitcoin/issues/15994
 double GuessVerificationProgress(const ChainTxData &data,
                                  const CBlockIndex *pindex) {
     if (pindex == nullptr) {
         return 0.0;
     }
 
     int64_t nNow = time(nullptr);
 
     double fTxTotal;
     if (pindex->GetChainTxCount() <= data.nTxCount) {
         fTxTotal = data.nTxCount + (nNow - data.nTime) * data.dTxRate;
     } else {
         fTxTotal = pindex->GetChainTxCount() +
                    (nNow - pindex->GetBlockTime()) * data.dTxRate;
     }
 
     return std::min<double>(pindex->GetChainTxCount() / fTxTotal, 1.0);
 }
 
 std::optional<BlockHash> ChainstateManager::SnapshotBlockhash() const {
     if (m_active_chainstate != nullptr) {
         // If a snapshot chainstate exists, it will always be our active.
         return m_active_chainstate->m_from_snapshot_blockhash;
     }
     return {};
 }
 
 std::vector<CChainState *> ChainstateManager::GetAll() {
     std::vector<CChainState *> out;
 
     if (!IsSnapshotValidated() && m_ibd_chainstate) {
         out.push_back(m_ibd_chainstate.get());
     }
 
     if (m_snapshot_chainstate) {
         out.push_back(m_snapshot_chainstate.get());
     }
 
     return out;
 }
 
 CChainState &
 ChainstateManager::InitializeChainstate(CTxMemPool &mempool,
                                         const BlockHash &snapshot_blockhash) {
     bool is_snapshot = !snapshot_blockhash.IsNull();
     std::unique_ptr<CChainState> &to_modify =
         is_snapshot ? m_snapshot_chainstate : m_ibd_chainstate;
 
     if (to_modify) {
         throw std::logic_error("should not be overwriting a chainstate");
     }
     to_modify.reset(new CChainState(mempool, m_blockman, snapshot_blockhash));
 
     // Snapshot chainstates and initial IBD chaintates always become active.
     if (is_snapshot || (!is_snapshot && !m_active_chainstate)) {
         LogPrintf("Switching active chainstate to %s\n", to_modify->ToString());
         m_active_chainstate = to_modify.get();
     } else {
         throw std::logic_error("unexpected chainstate activation");
     }
 
     return *to_modify;
 }
 
 CChainState &ChainstateManager::ActiveChainstate() const {
     assert(m_active_chainstate);
     return *m_active_chainstate;
 }
 
 bool ChainstateManager::IsSnapshotActive() const {
     return m_snapshot_chainstate &&
            m_active_chainstate == m_snapshot_chainstate.get();
 }
 
 CChainState &ChainstateManager::ValidatedChainstate() const {
     if (m_snapshot_chainstate && IsSnapshotValidated()) {
         return *m_snapshot_chainstate.get();
     }
     assert(m_ibd_chainstate);
     return *m_ibd_chainstate.get();
 }
 
 bool ChainstateManager::IsBackgroundIBD(CChainState *chainstate) const {
     return (m_snapshot_chainstate && chainstate == m_ibd_chainstate.get());
 }
 
 void ChainstateManager::Unload() {
     for (CChainState *chainstate : this->GetAll()) {
         chainstate->m_chain.SetTip(nullptr);
         chainstate->UnloadBlockIndex();
     }
 
     m_blockman.Unload();
 }
 
 void ChainstateManager::Reset() {
     m_ibd_chainstate.reset();
     m_snapshot_chainstate.reset();
     m_active_chainstate = nullptr;
     m_snapshot_validated = false;
 }
 
 void ChainstateManager::MaybeRebalanceCaches() {
     if (m_ibd_chainstate && !m_snapshot_chainstate) {
         LogPrintf("[snapshot] allocating all cache to the IBD chainstate\n");
         // Allocate everything to the IBD chainstate.
         m_ibd_chainstate->ResizeCoinsCaches(m_total_coinstip_cache,
                                             m_total_coinsdb_cache);
     } else if (m_snapshot_chainstate && !m_ibd_chainstate) {
         LogPrintf(
             "[snapshot] allocating all cache to the snapshot chainstate\n");
         // Allocate everything to the snapshot chainstate.
         m_snapshot_chainstate->ResizeCoinsCaches(m_total_coinstip_cache,
                                                  m_total_coinsdb_cache);
     } else if (m_ibd_chainstate && m_snapshot_chainstate) {
         // If both chainstates exist, determine who needs more cache based on
         // IBD status.
         //
         // Note: shrink caches first so that we don't inadvertently overwhelm
         // available memory.
         if (m_snapshot_chainstate->IsInitialBlockDownload()) {
             m_ibd_chainstate->ResizeCoinsCaches(m_total_coinstip_cache * 0.05,
                                                 m_total_coinsdb_cache * 0.05);
             m_snapshot_chainstate->ResizeCoinsCaches(
                 m_total_coinstip_cache * 0.95, m_total_coinsdb_cache * 0.95);
         } else {
             m_snapshot_chainstate->ResizeCoinsCaches(
                 m_total_coinstip_cache * 0.05, m_total_coinsdb_cache * 0.05);
             m_ibd_chainstate->ResizeCoinsCaches(m_total_coinstip_cache * 0.95,
                                                 m_total_coinsdb_cache * 0.95);
         }
     }
 }
diff --git a/src/validationinterface.cpp b/src/validationinterface.cpp
index 085c53acc..d5ec7ab65 100644
--- a/src/validationinterface.cpp
+++ b/src/validationinterface.cpp
@@ -1,275 +1,278 @@
 // Copyright (c) 2009-2010 Satoshi Nakamoto
 // Copyright (c) 2009-2016 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <validationinterface.h>
 
 #include <chain.h>
 #include <consensus/validation.h>
 #include <logging.h>
 #include <primitives/block.h>
 #include <primitives/transaction.h>
 #include <scheduler.h>
 
 #include <future>
 #include <tuple>
 #include <unordered_map>
 #include <utility>
 
 //! The MainSignalsInstance manages a list of shared_ptr<CValidationInterface>
 //! callbacks.
 //!
 //! A std::unordered_map is used to track what callbacks are currently
 //! registered, and a std::list is to used to store the callbacks that are
 //! currently registered as well as any callbacks that are just unregistered
 //! and about to be deleted when they are done executing.
 struct MainSignalsInstance {
 private:
     Mutex m_mutex;
     //! List entries consist of a callback pointer and reference count. The
     //! count is equal to the number of current executions of that entry, plus 1
     //! if it's registered. It cannot be 0 because that would imply it is
     //! unregistered and also not being executed (so shouldn't exist).
     struct ListEntry {
         std::shared_ptr<CValidationInterface> callbacks;
         int count = 1;
     };
     std::list<ListEntry> m_list GUARDED_BY(m_mutex);
     std::unordered_map<CValidationInterface *, std::list<ListEntry>::iterator>
         m_map GUARDED_BY(m_mutex);
 
 public:
     // We are not allowed to assume the scheduler only runs in one thread,
     // but must ensure all callbacks happen in-order, so we end up creating
     // our own queue here :(
     SingleThreadedSchedulerClient m_schedulerClient;
 
     explicit MainSignalsInstance(CScheduler *pscheduler)
         : m_schedulerClient(pscheduler) {}
 
     void Register(std::shared_ptr<CValidationInterface> callbacks) {
         LOCK(m_mutex);
         auto inserted = m_map.emplace(callbacks.get(), m_list.end());
         if (inserted.second) {
             inserted.first->second = m_list.emplace(m_list.end());
         }
         inserted.first->second->callbacks = std::move(callbacks);
     }
 
     void Unregister(CValidationInterface *callbacks) {
         LOCK(m_mutex);
         auto it = m_map.find(callbacks);
         if (it != m_map.end()) {
             if (!--it->second->count) {
                 m_list.erase(it->second);
             }
             m_map.erase(it);
         }
     }
 
     //! Clear unregisters every previously registered callback, erasing every
     //! map entry. After this call, the list may still contain callbacks that
     //! are currently executing, but it will be cleared when they are done
     //! executing.
     void Clear() {
         LOCK(m_mutex);
         for (const auto &entry : m_map) {
             if (!--entry.second->count) {
                 m_list.erase(entry.second);
             }
         }
         m_map.clear();
     }
 
     template <typename F> void Iterate(F &&f) {
         WAIT_LOCK(m_mutex, lock);
         for (auto it = m_list.begin(); it != m_list.end();) {
             ++it->count;
             {
                 REVERSE_LOCK(lock);
                 f(*it->callbacks);
             }
             it = --it->count ? std::next(it) : m_list.erase(it);
         }
     }
 };
 
 static CMainSignals g_signals;
 
 void CMainSignals::RegisterBackgroundSignalScheduler(CScheduler &scheduler) {
     assert(!m_internals);
     m_internals.reset(new MainSignalsInstance(&scheduler));
 }
 
 void CMainSignals::UnregisterBackgroundSignalScheduler() {
     m_internals.reset(nullptr);
 }
 
 void CMainSignals::FlushBackgroundCallbacks() {
     if (m_internals) {
         m_internals->m_schedulerClient.EmptyQueue();
     }
 }
 
 size_t CMainSignals::CallbacksPending() {
     if (!m_internals) {
         return 0;
     }
     return m_internals->m_schedulerClient.CallbacksPending();
 }
 
 CMainSignals &GetMainSignals() {
     return g_signals;
 }
 
 void RegisterSharedValidationInterface(
     std::shared_ptr<CValidationInterface> callbacks) {
     // Each connection captures the shared_ptr to ensure that each callback is
     // executed before the subscriber is destroyed. For more details see #18338.
     g_signals.m_internals->Register(std::move(callbacks));
 }
 
 void RegisterValidationInterface(CValidationInterface *callbacks) {
     // Create a shared_ptr with a no-op deleter - CValidationInterface lifecycle
     // is managed by the caller.
     RegisterSharedValidationInterface(
         {callbacks, [](CValidationInterface *) {}});
 }
 
 void UnregisterSharedValidationInterface(
     std::shared_ptr<CValidationInterface> callbacks) {
     UnregisterValidationInterface(callbacks.get());
 }
 
 void UnregisterValidationInterface(CValidationInterface *callbacks) {
     if (g_signals.m_internals) {
         g_signals.m_internals->Unregister(callbacks);
     }
 }
 
 void UnregisterAllValidationInterfaces() {
     if (!g_signals.m_internals) {
         return;
     }
     g_signals.m_internals->Clear();
 }
 
 void CallFunctionInValidationInterfaceQueue(std::function<void()> func) {
     g_signals.m_internals->m_schedulerClient.AddToProcessQueue(std::move(func));
 }
 
 void SyncWithValidationInterfaceQueue() {
     AssertLockNotHeld(cs_main);
     // Block until the validation queue drains
     std::promise<void> promise;
     CallFunctionInValidationInterfaceQueue([&promise] { promise.set_value(); });
     promise.get_future().wait();
 }
 
 // Use a macro instead of a function for conditional logging to prevent
 // evaluating arguments when logging is not enabled.
 //
 // NOTE: The lambda captures all local variables by value.
 #define ENQUEUE_AND_LOG_EVENT(event, fmt, name, ...)                           \
     do {                                                                       \
         auto local_name = (name);                                              \
         LOG_EVENT("Enqueuing " fmt, local_name, __VA_ARGS__);                  \
         m_internals->m_schedulerClient.AddToProcessQueue([=] {                 \
             LOG_EVENT(fmt, local_name, __VA_ARGS__);                           \
             event();                                                           \
         });                                                                    \
     } while (0)
 
 #define LOG_EVENT(fmt, ...) LogPrint(BCLog::VALIDATION, fmt "\n", __VA_ARGS__)
 
 void CMainSignals::UpdatedBlockTip(const CBlockIndex *pindexNew,
                                    const CBlockIndex *pindexFork,
                                    bool fInitialDownload) {
     // Dependencies exist that require UpdatedBlockTip events to be delivered in
     // the order in which the chain actually updates. One way to ensure this is
     // for the caller to invoke this signal in the same critical section where
     // the chain is updated
 
     auto event = [pindexNew, pindexFork, fInitialDownload, this] {
         m_internals->Iterate([&](CValidationInterface &callbacks) {
             callbacks.UpdatedBlockTip(pindexNew, pindexFork, fInitialDownload);
         });
     };
     ENQUEUE_AND_LOG_EVENT(
         event, "%s: new block hash=%s fork block hash=%s (in IBD=%s)", __func__,
         pindexNew->GetBlockHash().ToString(),
         pindexFork ? pindexFork->GetBlockHash().ToString() : "null",
         fInitialDownload);
 }
 
-void CMainSignals::TransactionAddedToMempool(const CTransactionRef &tx) {
-    auto event = [tx, this] {
+void CMainSignals::TransactionAddedToMempool(const CTransactionRef &tx,
+                                             uint64_t mempool_sequence) {
+    auto event = [tx, mempool_sequence, this] {
         m_internals->Iterate([&](CValidationInterface &callbacks) {
-            callbacks.TransactionAddedToMempool(tx);
+            callbacks.TransactionAddedToMempool(tx, mempool_sequence);
         });
     };
     ENQUEUE_AND_LOG_EVENT(event, "%s: txid=%s", __func__,
                           tx->GetHash().ToString());
 }
 
 void CMainSignals::TransactionRemovedFromMempool(const CTransactionRef &tx,
-                                                 MemPoolRemovalReason reason) {
-    auto event = [tx, reason, this] {
+                                                 MemPoolRemovalReason reason,
+                                                 uint64_t mempool_sequence) {
+    auto event = [tx, reason, mempool_sequence, this] {
         m_internals->Iterate([&](CValidationInterface &callbacks) {
-            callbacks.TransactionRemovedFromMempool(tx, reason);
+            callbacks.TransactionRemovedFromMempool(tx, reason,
+                                                    mempool_sequence);
         });
     };
     ENQUEUE_AND_LOG_EVENT(event, "%s: txid=%s", __func__,
                           tx->GetHash().ToString());
 }
 
 void CMainSignals::BlockConnected(const std::shared_ptr<const CBlock> &pblock,
                                   const CBlockIndex *pindex) {
     auto event = [pblock, pindex, this] {
         m_internals->Iterate([&](CValidationInterface &callbacks) {
             callbacks.BlockConnected(pblock, pindex);
         });
     };
     ENQUEUE_AND_LOG_EVENT(event, "%s: block hash=%s block height=%d", __func__,
                           pblock->GetHash().ToString(), pindex->nHeight);
 }
 
 void CMainSignals::BlockDisconnected(
     const std::shared_ptr<const CBlock> &pblock, const CBlockIndex *pindex) {
     auto event = [pblock, pindex, this] {
         m_internals->Iterate([&](CValidationInterface &callbacks) {
             callbacks.BlockDisconnected(pblock, pindex);
         });
     };
     ENQUEUE_AND_LOG_EVENT(event, "%s: block hash=%s", __func__,
                           pblock->GetHash().ToString());
 }
 
 void CMainSignals::ChainStateFlushed(const CBlockLocator &locator) {
     auto event = [locator, this] {
         m_internals->Iterate([&](CValidationInterface &callbacks) {
             callbacks.ChainStateFlushed(locator);
         });
     };
     ENQUEUE_AND_LOG_EVENT(event, "%s: block hash=%s", __func__,
                           locator.IsNull() ? "null"
                                            : locator.vHave.front().ToString());
 }
 
 void CMainSignals::BlockChecked(const CBlock &block,
                                 const BlockValidationState &state) {
     LOG_EVENT("%s: block hash=%s state=%s", __func__,
               block.GetHash().ToString(), state.ToString());
     m_internals->Iterate([&](CValidationInterface &callbacks) {
         callbacks.BlockChecked(block, state);
     });
 }
 
 void CMainSignals::NewPoWValidBlock(
     const CBlockIndex *pindex, const std::shared_ptr<const CBlock> &block) {
     LOG_EVENT("%s: block hash=%s", __func__, block->GetHash().ToString());
     m_internals->Iterate([&](CValidationInterface &callbacks) {
         callbacks.NewPoWValidBlock(pindex, block);
     });
 }
diff --git a/src/validationinterface.h b/src/validationinterface.h
index d5ad1fd4d..5876e2aca 100644
--- a/src/validationinterface.h
+++ b/src/validationinterface.h
@@ -1,237 +1,242 @@
 // Copyright (c) 2009-2010 Satoshi Nakamoto
 // Copyright (c) 2009-2016 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #ifndef BITCOIN_VALIDATIONINTERFACE_H
 #define BITCOIN_VALIDATIONINTERFACE_H
 
 #include <primitives/transaction.h> // CTransaction(Ref)
 #include <sync.h>
 
 #include <functional>
 #include <memory>
 
 extern RecursiveMutex cs_main;
 class BlockValidationState;
 class CBlock;
 class CBlockIndex;
 struct CBlockLocator;
 class CConnman;
 class CValidationInterface;
 class uint256;
 class CScheduler;
 enum class MemPoolRemovalReason;
 
 /** Register subscriber */
 void RegisterValidationInterface(CValidationInterface *callbacks);
 /**
  * Unregister subscriber. DEPRECATED. This is not safe to use when the RPC
  * server or main message handler thread is running.
  */
 void UnregisterValidationInterface(CValidationInterface *callbacks);
 /** Unregister all subscribers */
 void UnregisterAllValidationInterfaces();
 
 // Alternate registration functions that release a shared_ptr after the last
 // notification is sent. These are useful for race-free cleanup, since
 // unregistration is nonblocking and can return before the last notification is
 // processed.
 /** Register subscriber */
 void RegisterSharedValidationInterface(
     std::shared_ptr<CValidationInterface> callbacks);
 /** Unregister subscriber */
 void UnregisterSharedValidationInterface(
     std::shared_ptr<CValidationInterface> callbacks);
 
 /**
  * Pushes a function to callback onto the notification queue, guaranteeing any
  * callbacks generated prior to now are finished when the function is called.
  *
  * Be very careful blocking on func to be called if any locks are held -
  * validation interface clients may not be able to make progress as they often
  * wait for things like cs_main, so blocking until func is called with cs_main
  * will result in a deadlock (that DEBUG_LOCKORDER will miss).
  */
 void CallFunctionInValidationInterfaceQueue(std::function<void()> func);
 /**
  * This is a synonym for the following, which asserts certain locks are not
  * held:
  *     std::promise<void> promise;
  *     CallFunctionInValidationInterfaceQueue([&promise] {
  *         promise.set_value();
  *     });
  *     promise.get_future().wait();
  */
 void SyncWithValidationInterfaceQueue() LOCKS_EXCLUDED(cs_main);
 
 /**
  * Implement this to subscribe to events generated in validation
  *
  * Each CValidationInterface() subscriber will receive event callbacks
  * in the order in which the events were generated by validation.
  * Furthermore, each ValidationInterface() subscriber may assume that
  * callbacks effectively run in a single thread with single-threaded
  * memory consistency. That is, for a given ValidationInterface()
  * instantiation, each callback will complete before the next one is
  * invoked. This means, for example when a block is connected that the
  * UpdatedBlockTip() callback may depend on an operation performed in
  * the BlockConnected() callback without worrying about explicit
  * synchronization. No ordering should be assumed across
  * ValidationInterface() subscribers.
  */
 class CValidationInterface {
 protected:
     /**
      * Protected destructor so that instances can only be deleted by derived
      * classes. If that restriction is no longer desired, this should be made
      * public and virtual.
      */
     ~CValidationInterface() = default;
     /**
      * Notifies listeners when the block chain tip advances.
      *
      * When multiple blocks are connected at once, UpdatedBlockTip will be
      * called on the final tip but may not be called on every intermediate tip.
      * If the latter behavior is desired, subscribe to BlockConnected() instead.
      *
      * Called on a background thread.
      */
     virtual void UpdatedBlockTip(const CBlockIndex *pindexNew,
                                  const CBlockIndex *pindexFork,
                                  bool fInitialDownload) {}
     /**
      * Notifies listeners of a transaction having been added to mempool.
      *
      * Called on a background thread.
      */
-    virtual void TransactionAddedToMempool(const CTransactionRef &tx) {}
+    virtual void TransactionAddedToMempool(const CTransactionRef &tx,
+                                           uint64_t mempool_sequence) {}
+
     /**
      * Notifies listeners of a transaction leaving mempool.
      *
      * This notification fires for transactions that are removed from the
      * mempool for the following reasons:
      *
      * - EXPIRY (expired from mempool after -mempoolexpiry hours)
      * - SIZELIMIT (removed in size limiting if the mempool exceeds -maxmempool
      *   megabytes)
      * - REORG (removed during a reorg)
      * - CONFLICT (removed because it conflicts with in-block transaction)
      *
      * This does not fire for transactions that are removed from the mempool
      * because they have been included in a block. Any client that is interested
      * in transactions removed from the mempool for inclusion in a block can
      * learn about those transactions from the BlockConnected notification.
      *
      * Transactions that are removed from the mempool because they conflict
      * with a transaction in the new block will have
      * TransactionRemovedFromMempool events fired *before* the BlockConnected
      * event is fired. If multiple blocks are connected in one step, then the
      * ordering could be:
      *
      * - TransactionRemovedFromMempool(tx1 from block A)
      * - TransactionRemovedFromMempool(tx2 from block A)
      * - TransactionRemovedFromMempool(tx1 from block B)
      * - TransactionRemovedFromMempool(tx2 from block B)
      * - BlockConnected(A)
      * - BlockConnected(B)
      *
      * Called on a background thread.
      */
     virtual void TransactionRemovedFromMempool(const CTransactionRef &tx,
-                                               MemPoolRemovalReason reason) {}
+                                               MemPoolRemovalReason reason,
+                                               uint64_t mempool_sequence) {}
     /**
      * Notifies listeners of a block being connected.
      * Provides a vector of transactions evicted from the mempool as a result.
      *
      * Called on a background thread.
      */
     virtual void BlockConnected(const std::shared_ptr<const CBlock> &block,
                                 const CBlockIndex *pindex) {}
     /**
      * Notifies listeners of a block being disconnected
      *
      * Called on a background thread.
      */
     virtual void BlockDisconnected(const std::shared_ptr<const CBlock> &block,
                                    const CBlockIndex *pindex) {}
     /**
      * Notifies listeners of the new active block chain on-disk.
      *
      * Prior to this callback, any updates are not guaranteed to persist on disk
      * (ie clients need to handle shutdown/restart safety by being able to
      * understand when some updates were lost due to unclean shutdown).
      *
      * When this callback is invoked, the validation changes done by any prior
      * callback are guaranteed to exist on disk and survive a restart, including
      * an unclean shutdown.
      *
      * Provides a locator describing the best chain, which is likely useful for
      * storing current state on disk in client DBs.
      *
      * Called on a background thread.
      */
     virtual void ChainStateFlushed(const CBlockLocator &locator) {}
     /**
      * Notifies listeners of a block validation result.
      * If the provided BlockValidationState IsValid, the provided block
      * is guaranteed to be the current best block at the time the
      * callback was generated (not necessarily now)
      */
     virtual void BlockChecked(const CBlock &, const BlockValidationState &) {}
     /**
      * Notifies listeners that a block which builds directly on our current tip
      * has been received and connected to the headers tree, though not validated
      * yet.
      */
     virtual void NewPoWValidBlock(const CBlockIndex *pindex,
                                   const std::shared_ptr<const CBlock> &block){};
     friend class CMainSignals;
 };
 
 struct MainSignalsInstance;
 class CMainSignals {
 private:
     std::unique_ptr<MainSignalsInstance> m_internals;
 
     friend void ::RegisterSharedValidationInterface(
         std::shared_ptr<CValidationInterface>);
     friend void ::UnregisterValidationInterface(CValidationInterface *);
     friend void ::UnregisterAllValidationInterfaces();
     friend void ::CallFunctionInValidationInterfaceQueue(
         std::function<void()> func);
 
 public:
     /**
      * Register a CScheduler to give callbacks which should run in the
      * background (may only be called once)
      */
     void RegisterBackgroundSignalScheduler(CScheduler &scheduler);
     /**
      * Unregister a CScheduler to give callbacks which should run in the
      * background - these callbacks will now be dropped!
      */
     void UnregisterBackgroundSignalScheduler();
     /** Call any remaining callbacks on the calling thread */
     void FlushBackgroundCallbacks();
 
     size_t CallbacksPending();
 
     void UpdatedBlockTip(const CBlockIndex *, const CBlockIndex *,
                          bool fInitialDownload);
-    void TransactionAddedToMempool(const CTransactionRef &);
+    void TransactionAddedToMempool(const CTransactionRef &,
+                                   uint64_t mempool_sequence);
     void TransactionRemovedFromMempool(const CTransactionRef &,
-                                       MemPoolRemovalReason);
+                                       MemPoolRemovalReason,
+                                       uint64_t mempool_sequence);
     void BlockConnected(const std::shared_ptr<const CBlock> &,
                         const CBlockIndex *pindex);
     void BlockDisconnected(const std::shared_ptr<const CBlock> &,
                            const CBlockIndex *pindex);
     void ChainStateFlushed(const CBlockLocator &);
     void BlockChecked(const CBlock &, const BlockValidationState &);
     void NewPoWValidBlock(const CBlockIndex *,
                           const std::shared_ptr<const CBlock> &);
 };
 
 CMainSignals &GetMainSignals();
 
 #endif // BITCOIN_VALIDATIONINTERFACE_H
diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index b36a636c3..7fe34b693 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -1,5091 +1,5094 @@
 // Copyright (c) 2009-2010 Satoshi Nakamoto
 // Copyright (c) 2009-2019 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <wallet/wallet.h>
 
 #include <chain.h>
 #include <chainparams.h>
 #include <config.h>
 #include <consensus/consensus.h>
 #include <consensus/validation.h>
 #include <fs.h>
 #include <interfaces/wallet.h>
 #include <key.h>
 #include <key_io.h>
 #include <policy/mempool.h>
 #include <policy/policy.h>
 #include <primitives/transaction.h>
 #include <random.h>
 #include <script/descriptor.h>
 #include <script/script.h>
 #include <script/sighashtype.h>
 #include <script/sign.h>
 #include <script/signingprovider.h>
 #include <txmempool.h>
 #include <univalue.h>
 #include <util/bip32.h>
 #include <util/check.h>
 #include <util/error.h>
 #include <util/moneystr.h>
 #include <util/string.h>
 #include <util/translation.h>
 #include <wallet/coincontrol.h>
 #include <wallet/fees.h>
 
 #include <boost/algorithm/string/replace.hpp>
 
 using interfaces::FoundBlock;
 
 const std::map<uint64_t, std::string> WALLET_FLAG_CAVEATS{
     {WALLET_FLAG_AVOID_REUSE,
      "You need to rescan the blockchain in order to correctly mark used "
      "destinations in the past. Until this is done, some destinations may "
      "be considered unused, even if the opposite is the case."},
 };
 
 static RecursiveMutex cs_wallets;
 static std::vector<std::shared_ptr<CWallet>> vpwallets GUARDED_BY(cs_wallets);
 static std::list<LoadWalletFn> g_load_wallet_fns GUARDED_BY(cs_wallets);
 
 bool AddWalletSetting(interfaces::Chain &chain,
                       const std::string &wallet_name) {
     util::SettingsValue setting_value = chain.getRwSetting("wallet");
     if (!setting_value.isArray()) {
         setting_value.setArray();
     }
     for (const util::SettingsValue &value : setting_value.getValues()) {
         if (value.isStr() && value.get_str() == wallet_name) {
             return true;
         }
     }
     setting_value.push_back(wallet_name);
     return chain.updateRwSetting("wallet", setting_value);
 }
 
 bool RemoveWalletSetting(interfaces::Chain &chain,
                          const std::string &wallet_name) {
     util::SettingsValue setting_value = chain.getRwSetting("wallet");
     if (!setting_value.isArray()) {
         return true;
     }
     util::SettingsValue new_value(util::SettingsValue::VARR);
     for (const util::SettingsValue &value : setting_value.getValues()) {
         if (!value.isStr() || value.get_str() != wallet_name) {
             new_value.push_back(value);
         }
     }
     if (new_value.size() == setting_value.size()) {
         return true;
     }
     return chain.updateRwSetting("wallet", new_value);
 }
 
 static void UpdateWalletSetting(interfaces::Chain &chain,
                                 const std::string &wallet_name,
                                 std::optional<bool> load_on_startup,
                                 std::vector<bilingual_str> &warnings) {
     if (!load_on_startup) {
         return;
     }
     if (load_on_startup.value() && !AddWalletSetting(chain, wallet_name)) {
         warnings.emplace_back(
             Untranslated("Wallet load on startup setting could not be updated, "
                          "so wallet may not be loaded next node startup."));
     } else if (!load_on_startup.value() &&
                !RemoveWalletSetting(chain, wallet_name)) {
         warnings.emplace_back(
             Untranslated("Wallet load on startup setting could not be updated, "
                          "so wallet may still be loaded next node startup."));
     }
 }
 
 bool AddWallet(const std::shared_ptr<CWallet> &wallet) {
     LOCK(cs_wallets);
     assert(wallet);
     std::vector<std::shared_ptr<CWallet>>::const_iterator i =
         std::find(vpwallets.begin(), vpwallets.end(), wallet);
     if (i != vpwallets.end()) {
         return false;
     }
     vpwallets.push_back(wallet);
     wallet->ConnectScriptPubKeyManNotifiers();
     return true;
 }
 
 bool RemoveWallet(const std::shared_ptr<CWallet> &wallet,
                   std::optional<bool> load_on_start,
                   std::vector<bilingual_str> &warnings) {
     assert(wallet);
 
     interfaces::Chain &chain = wallet->chain();
     std::string name = wallet->GetName();
 
     // Unregister with the validation interface which also drops shared ponters.
     wallet->m_chain_notifications_handler.reset();
     LOCK(cs_wallets);
     std::vector<std::shared_ptr<CWallet>>::iterator i =
         std::find(vpwallets.begin(), vpwallets.end(), wallet);
     if (i == vpwallets.end()) {
         return false;
     }
     vpwallets.erase(i);
 
     // Write the wallet setting
     UpdateWalletSetting(chain, name, load_on_start, warnings);
 
     return true;
 }
 
 bool RemoveWallet(const std::shared_ptr<CWallet> &wallet,
                   std::optional<bool> load_on_start) {
     std::vector<bilingual_str> warnings;
     return RemoveWallet(wallet, load_on_start, warnings);
 }
 
 std::vector<std::shared_ptr<CWallet>> GetWallets() {
     LOCK(cs_wallets);
     return vpwallets;
 }
 
 std::shared_ptr<CWallet> GetWallet(const std::string &name) {
     LOCK(cs_wallets);
     for (const std::shared_ptr<CWallet> &wallet : vpwallets) {
         if (wallet->GetName() == name) {
             return wallet;
         }
     }
     return nullptr;
 }
 
 std::unique_ptr<interfaces::Handler>
 HandleLoadWallet(LoadWalletFn load_wallet) {
     LOCK(cs_wallets);
     auto it = g_load_wallet_fns.emplace(g_load_wallet_fns.end(),
                                         std::move(load_wallet));
     return interfaces::MakeHandler([it] {
         LOCK(cs_wallets);
         g_load_wallet_fns.erase(it);
     });
 }
 
 static Mutex g_loading_wallet_mutex;
 static Mutex g_wallet_release_mutex;
 static std::condition_variable g_wallet_release_cv;
 static std::set<std::string>
     g_loading_wallet_set GUARDED_BY(g_loading_wallet_mutex);
 static std::set<std::string>
     g_unloading_wallet_set GUARDED_BY(g_wallet_release_mutex);
 
 // Custom deleter for shared_ptr<CWallet>.
 static void ReleaseWallet(CWallet *wallet) {
     const std::string name = wallet->GetName();
     wallet->WalletLogPrintf("Releasing wallet\n");
     wallet->Flush();
     delete wallet;
     // Wallet is now released, notify UnloadWallet, if any.
     {
         LOCK(g_wallet_release_mutex);
         if (g_unloading_wallet_set.erase(name) == 0) {
             // UnloadWallet was not called for this wallet, all done.
             return;
         }
     }
     g_wallet_release_cv.notify_all();
 }
 
 void UnloadWallet(std::shared_ptr<CWallet> &&wallet) {
     // Mark wallet for unloading.
     const std::string name = wallet->GetName();
     {
         LOCK(g_wallet_release_mutex);
         auto it = g_unloading_wallet_set.insert(name);
         assert(it.second);
     }
     // The wallet can be in use so it's not possible to explicitly unload here.
     // Notify the unload intent so that all remaining shared pointers are
     // released.
     wallet->NotifyUnload();
 
     // Time to ditch our shared_ptr and wait for ReleaseWallet call.
     wallet.reset();
     {
         WAIT_LOCK(g_wallet_release_mutex, lock);
         while (g_unloading_wallet_set.count(name) == 1) {
             g_wallet_release_cv.wait(lock);
         }
     }
 }
 
 static const size_t OUTPUT_GROUP_MAX_ENTRIES = 10;
 
 namespace {
 std::shared_ptr<CWallet>
 LoadWalletInternal(interfaces::Chain &chain, const std::string &name,
                    std::optional<bool> load_on_start,
                    const DatabaseOptions &options, DatabaseStatus &status,
                    bilingual_str &error, std::vector<bilingual_str> &warnings) {
     try {
         std::unique_ptr<WalletDatabase> database =
             MakeWalletDatabase(name, options, status, error);
         if (!database) {
             error = Untranslated("Wallet file verification failed.") +
                     Untranslated(" ") + error;
             return nullptr;
         }
 
         std::shared_ptr<CWallet> wallet =
             CWallet::Create(chain, name, std::move(database),
                             options.create_flags, error, warnings);
         if (!wallet) {
             error = Untranslated("Wallet loading failed.") + Untranslated(" ") +
                     error;
             status = DatabaseStatus::FAILED_LOAD;
             return nullptr;
         }
         AddWallet(wallet);
         wallet->postInitProcess();
 
         // Write the wallet setting
         UpdateWalletSetting(chain, name, load_on_start, warnings);
 
         return wallet;
     } catch (const std::runtime_error &e) {
         error = Untranslated(e.what());
         status = DatabaseStatus::FAILED_LOAD;
         return nullptr;
     }
 }
 } // namespace
 
 std::shared_ptr<CWallet>
 LoadWallet(interfaces::Chain &chain, const std::string &name,
            std::optional<bool> load_on_start, const DatabaseOptions &options,
            DatabaseStatus &status, bilingual_str &error,
            std::vector<bilingual_str> &warnings) {
     auto result = WITH_LOCK(g_loading_wallet_mutex,
                             return g_loading_wallet_set.insert(name));
     if (!result.second) {
         error = Untranslated("Wallet already being loading.");
         status = DatabaseStatus::FAILED_LOAD;
         return nullptr;
     }
     auto wallet = LoadWalletInternal(chain, name, load_on_start, options,
                                      status, error, warnings);
     WITH_LOCK(g_loading_wallet_mutex, g_loading_wallet_set.erase(result.first));
     return wallet;
 }
 
 std::shared_ptr<CWallet>
 CreateWallet(interfaces::Chain &chain, const std::string &name,
              std::optional<bool> load_on_start, const DatabaseOptions &options,
              DatabaseStatus &status, bilingual_str &error,
              std::vector<bilingual_str> &warnings) {
     uint64_t wallet_creation_flags = options.create_flags;
     const SecureString &passphrase = options.create_passphrase;
 
     // Indicate that the wallet is actually supposed to be blank and not just
     // blank to make it encrypted
     bool create_blank = (wallet_creation_flags & WALLET_FLAG_BLANK_WALLET);
 
     // Born encrypted wallets need to be created blank first.
     if (!passphrase.empty()) {
         wallet_creation_flags |= WALLET_FLAG_BLANK_WALLET;
     }
 
     // Wallet::Verify will check if we're trying to create a wallet with a
     // duplicate name.
     std::unique_ptr<WalletDatabase> database =
         MakeWalletDatabase(name, options, status, error);
     if (!database) {
         error = Untranslated("Wallet file verification failed.") +
                 Untranslated(" ") + error;
         status = DatabaseStatus::FAILED_VERIFY;
         return nullptr;
     }
 
     // Do not allow a passphrase when private keys are disabled
     if (!passphrase.empty() &&
         (wallet_creation_flags & WALLET_FLAG_DISABLE_PRIVATE_KEYS)) {
         error = Untranslated(
             "Passphrase provided but private keys are disabled. A passphrase "
             "is only used to encrypt private keys, so cannot be used for "
             "wallets with private keys disabled.");
         status = DatabaseStatus::FAILED_CREATE;
         return nullptr;
     }
 
     // Make the wallet
     std::shared_ptr<CWallet> wallet =
         CWallet::Create(chain, name, std::move(database), wallet_creation_flags,
                         error, warnings);
     if (!wallet) {
         error =
             Untranslated("Wallet creation failed.") + Untranslated(" ") + error;
         status = DatabaseStatus::FAILED_CREATE;
         return nullptr;
     }
 
     // Encrypt the wallet
     if (!passphrase.empty() &&
         !(wallet_creation_flags & WALLET_FLAG_DISABLE_PRIVATE_KEYS)) {
         if (!wallet->EncryptWallet(passphrase)) {
             error =
                 Untranslated("Error: Wallet created but failed to encrypt.");
             status = DatabaseStatus::FAILED_ENCRYPT;
             return nullptr;
         }
         if (!create_blank) {
             // Unlock the wallet
             if (!wallet->Unlock(passphrase)) {
                 error = Untranslated(
                     "Error: Wallet was encrypted but could not be unlocked");
                 status = DatabaseStatus::FAILED_ENCRYPT;
                 return nullptr;
             }
 
             // Set a seed for the wallet
             {
                 LOCK(wallet->cs_wallet);
                 if (wallet->IsWalletFlagSet(WALLET_FLAG_DESCRIPTORS)) {
                     wallet->SetupDescriptorScriptPubKeyMans();
                 } else {
                     for (auto spk_man : wallet->GetActiveScriptPubKeyMans()) {
                         if (!spk_man->SetupGeneration()) {
                             error =
                                 Untranslated("Unable to generate initial keys");
                             status = DatabaseStatus::FAILED_CREATE;
                             return nullptr;
                         }
                     }
                 }
             }
 
             // Relock the wallet
             wallet->Lock();
         }
     }
     AddWallet(wallet);
     wallet->postInitProcess();
 
     // Write the wallet settings
     UpdateWalletSetting(chain, name, load_on_start, warnings);
 
     status = DatabaseStatus::SUCCESS;
     return wallet;
 }
 
 /** @defgroup mapWallet
  *
  * @{
  */
 
 std::string COutput::ToString() const {
     return strprintf("COutput(%s, %d, %d) [%s]", tx->GetId().ToString(), i,
                      nDepth, FormatMoney(tx->tx->vout[i].nValue));
 }
 
 const CChainParams &CWallet::GetChainParams() const {
     // Get CChainParams from interfaces::Chain, unless wallet doesn't have a
     // chain (i.e. bitcoin-wallet), in which case return global Params()
     return m_chain ? m_chain->params() : Params();
 }
 
 const CWalletTx *CWallet::GetWalletTx(const TxId &txid) const {
     AssertLockHeld(cs_wallet);
     std::map<TxId, CWalletTx>::const_iterator it = mapWallet.find(txid);
     if (it == mapWallet.end()) {
         return nullptr;
     }
 
     return &(it->second);
 }
 
 void CWallet::UpgradeKeyMetadata() {
     if (IsLocked() || IsWalletFlagSet(WALLET_FLAG_KEY_ORIGIN_METADATA)) {
         return;
     }
 
     auto spk_man = GetLegacyScriptPubKeyMan();
     if (!spk_man) {
         return;
     }
 
     spk_man->UpgradeKeyMetadata();
     SetWalletFlag(WALLET_FLAG_KEY_ORIGIN_METADATA);
 }
 
 bool CWallet::Unlock(const SecureString &strWalletPassphrase,
                      bool accept_no_keys) {
     CCrypter crypter;
     CKeyingMaterial _vMasterKey;
 
     {
         LOCK(cs_wallet);
         for (const MasterKeyMap::value_type &pMasterKey : mapMasterKeys) {
             if (!crypter.SetKeyFromPassphrase(
                     strWalletPassphrase, pMasterKey.second.vchSalt,
                     pMasterKey.second.nDeriveIterations,
                     pMasterKey.second.nDerivationMethod)) {
                 return false;
             }
             if (!crypter.Decrypt(pMasterKey.second.vchCryptedKey,
                                  _vMasterKey)) {
                 // try another master key
                 continue;
             }
             if (Unlock(_vMasterKey, accept_no_keys)) {
                 // Now that we've unlocked, upgrade the key metadata
                 UpgradeKeyMetadata();
                 return true;
             }
         }
     }
 
     return false;
 }
 
 bool CWallet::ChangeWalletPassphrase(
     const SecureString &strOldWalletPassphrase,
     const SecureString &strNewWalletPassphrase) {
     bool fWasLocked = IsLocked();
 
     LOCK(cs_wallet);
     Lock();
 
     CCrypter crypter;
     CKeyingMaterial _vMasterKey;
     for (MasterKeyMap::value_type &pMasterKey : mapMasterKeys) {
         if (!crypter.SetKeyFromPassphrase(
                 strOldWalletPassphrase, pMasterKey.second.vchSalt,
                 pMasterKey.second.nDeriveIterations,
                 pMasterKey.second.nDerivationMethod)) {
             return false;
         }
 
         if (!crypter.Decrypt(pMasterKey.second.vchCryptedKey, _vMasterKey)) {
             return false;
         }
 
         if (Unlock(_vMasterKey)) {
             int64_t nStartTime = GetTimeMillis();
             crypter.SetKeyFromPassphrase(strNewWalletPassphrase,
                                          pMasterKey.second.vchSalt,
                                          pMasterKey.second.nDeriveIterations,
                                          pMasterKey.second.nDerivationMethod);
             pMasterKey.second.nDeriveIterations = static_cast<unsigned int>(
                 pMasterKey.second.nDeriveIterations *
                 (100 / ((double)(GetTimeMillis() - nStartTime))));
 
             nStartTime = GetTimeMillis();
             crypter.SetKeyFromPassphrase(strNewWalletPassphrase,
                                          pMasterKey.second.vchSalt,
                                          pMasterKey.second.nDeriveIterations,
                                          pMasterKey.second.nDerivationMethod);
             pMasterKey.second.nDeriveIterations =
                 (pMasterKey.second.nDeriveIterations +
                  static_cast<unsigned int>(
                      pMasterKey.second.nDeriveIterations * 100 /
                      double(GetTimeMillis() - nStartTime))) /
                 2;
 
             if (pMasterKey.second.nDeriveIterations < 25000) {
                 pMasterKey.second.nDeriveIterations = 25000;
             }
 
             WalletLogPrintf(
                 "Wallet passphrase changed to an nDeriveIterations of %i\n",
                 pMasterKey.second.nDeriveIterations);
 
             if (!crypter.SetKeyFromPassphrase(
                     strNewWalletPassphrase, pMasterKey.second.vchSalt,
                     pMasterKey.second.nDeriveIterations,
                     pMasterKey.second.nDerivationMethod)) {
                 return false;
             }
 
             if (!crypter.Encrypt(_vMasterKey,
                                  pMasterKey.second.vchCryptedKey)) {
                 return false;
             }
 
             WalletBatch(*database).WriteMasterKey(pMasterKey.first,
                                                   pMasterKey.second);
             if (fWasLocked) {
                 Lock();
             }
 
             return true;
         }
     }
 
     return false;
 }
 
 void CWallet::chainStateFlushed(const CBlockLocator &loc) {
     WalletBatch batch(*database);
     batch.WriteBestBlock(loc);
 }
 
 void CWallet::SetMinVersion(enum WalletFeature nVersion, WalletBatch *batch_in,
                             bool fExplicit) {
     LOCK(cs_wallet);
     if (nWalletVersion >= nVersion) {
         return;
     }
 
     // When doing an explicit upgrade, if we pass the max version permitted,
     // upgrade all the way.
     if (fExplicit && nVersion > nWalletMaxVersion) {
         nVersion = FEATURE_LATEST;
     }
 
     nWalletVersion = nVersion;
 
     if (nVersion > nWalletMaxVersion) {
         nWalletMaxVersion = nVersion;
     }
 
     WalletBatch *batch = batch_in ? batch_in : new WalletBatch(*database);
     if (nWalletVersion > 40000) {
         batch->WriteMinVersion(nWalletVersion);
     }
     if (!batch_in) {
         delete batch;
     }
 }
 
 bool CWallet::SetMaxVersion(int nVersion) {
     LOCK(cs_wallet);
 
     // Cannot downgrade below current version
     if (nWalletVersion > nVersion) {
         return false;
     }
 
     nWalletMaxVersion = nVersion;
 
     return true;
 }
 
 std::set<TxId> CWallet::GetConflicts(const TxId &txid) const {
     std::set<TxId> result;
     AssertLockHeld(cs_wallet);
 
     std::map<TxId, CWalletTx>::const_iterator it = mapWallet.find(txid);
     if (it == mapWallet.end()) {
         return result;
     }
 
     const CWalletTx &wtx = it->second;
 
     std::pair<TxSpends::const_iterator, TxSpends::const_iterator> range;
 
     for (const CTxIn &txin : wtx.tx->vin) {
         if (mapTxSpends.count(txin.prevout) <= 1) {
             // No conflict if zero or one spends.
             continue;
         }
 
         range = mapTxSpends.equal_range(txin.prevout);
         for (TxSpends::const_iterator _it = range.first; _it != range.second;
              ++_it) {
             result.insert(_it->second);
         }
     }
 
     return result;
 }
 
 bool CWallet::HasWalletSpend(const TxId &txid) const {
     AssertLockHeld(cs_wallet);
     auto iter = mapTxSpends.lower_bound(COutPoint(txid, 0));
     return (iter != mapTxSpends.end() && iter->first.GetTxId() == txid);
 }
 
 void CWallet::Flush() {
     database->Flush();
 }
 
 void CWallet::Close() {
     database->Close();
 }
 
 void CWallet::SyncMetaData(
     std::pair<TxSpends::iterator, TxSpends::iterator> range) {
     // We want all the wallet transactions in range to have the same metadata as
     // the oldest (smallest nOrderPos).
     // So: find smallest nOrderPos:
 
     int nMinOrderPos = std::numeric_limits<int>::max();
     const CWalletTx *copyFrom = nullptr;
     for (TxSpends::iterator it = range.first; it != range.second; ++it) {
         const CWalletTx *wtx = &mapWallet.at(it->second);
         if (wtx->nOrderPos < nMinOrderPos) {
             nMinOrderPos = wtx->nOrderPos;
             copyFrom = wtx;
         }
     }
 
     if (!copyFrom) {
         return;
     }
 
     // Now copy data from copyFrom to rest:
     for (TxSpends::iterator it = range.first; it != range.second; ++it) {
         const TxId &txid = it->second;
         CWalletTx *copyTo = &mapWallet.at(txid);
         if (copyFrom == copyTo) {
             continue;
         }
 
         assert(
             copyFrom &&
             "Oldest wallet transaction in range assumed to have been found.");
 
         if (!copyFrom->IsEquivalentTo(*copyTo)) {
             continue;
         }
 
         copyTo->mapValue = copyFrom->mapValue;
         copyTo->vOrderForm = copyFrom->vOrderForm;
         // fTimeReceivedIsTxTime not copied on purpose nTimeReceived not copied
         // on purpose.
         copyTo->nTimeSmart = copyFrom->nTimeSmart;
         copyTo->fFromMe = copyFrom->fFromMe;
         // nOrderPos not copied on purpose cached members not copied on purpose.
     }
 }
 
 /**
  * Outpoint is spent if any non-conflicted transaction, spends it:
  */
 bool CWallet::IsSpent(const COutPoint &outpoint) const {
     std::pair<TxSpends::const_iterator, TxSpends::const_iterator> range =
         mapTxSpends.equal_range(outpoint);
 
     for (TxSpends::const_iterator it = range.first; it != range.second; ++it) {
         const TxId &wtxid = it->second;
         std::map<TxId, CWalletTx>::const_iterator mit = mapWallet.find(wtxid);
         if (mit != mapWallet.end()) {
             int depth = mit->second.GetDepthInMainChain();
             if (depth > 0 || (depth == 0 && !mit->second.isAbandoned())) {
                 // Spent
                 return true;
             }
         }
     }
 
     return false;
 }
 
 void CWallet::AddToSpends(const COutPoint &outpoint, const TxId &wtxid) {
     mapTxSpends.insert(std::make_pair(outpoint, wtxid));
 
     setLockedCoins.erase(outpoint);
 
     std::pair<TxSpends::iterator, TxSpends::iterator> range;
     range = mapTxSpends.equal_range(outpoint);
     SyncMetaData(range);
 }
 
 void CWallet::AddToSpends(const TxId &wtxid) {
     auto it = mapWallet.find(wtxid);
     assert(it != mapWallet.end());
     CWalletTx &thisTx = it->second;
     // Coinbases don't spend anything!
     if (thisTx.IsCoinBase()) {
         return;
     }
 
     for (const CTxIn &txin : thisTx.tx->vin) {
         AddToSpends(txin.prevout, wtxid);
     }
 }
 
 bool CWallet::EncryptWallet(const SecureString &strWalletPassphrase) {
     if (IsCrypted()) {
         return false;
     }
 
     CKeyingMaterial _vMasterKey;
 
     _vMasterKey.resize(WALLET_CRYPTO_KEY_SIZE);
     GetStrongRandBytes(&_vMasterKey[0], WALLET_CRYPTO_KEY_SIZE);
 
     CMasterKey kMasterKey;
 
     kMasterKey.vchSalt.resize(WALLET_CRYPTO_SALT_SIZE);
     GetStrongRandBytes(&kMasterKey.vchSalt[0], WALLET_CRYPTO_SALT_SIZE);
 
     CCrypter crypter;
     int64_t nStartTime = GetTimeMillis();
     crypter.SetKeyFromPassphrase(strWalletPassphrase, kMasterKey.vchSalt, 25000,
                                  kMasterKey.nDerivationMethod);
     kMasterKey.nDeriveIterations = static_cast<unsigned int>(
         2500000 / double(GetTimeMillis() - nStartTime));
 
     nStartTime = GetTimeMillis();
     crypter.SetKeyFromPassphrase(strWalletPassphrase, kMasterKey.vchSalt,
                                  kMasterKey.nDeriveIterations,
                                  kMasterKey.nDerivationMethod);
     kMasterKey.nDeriveIterations =
         (kMasterKey.nDeriveIterations +
          static_cast<unsigned int>(kMasterKey.nDeriveIterations * 100 /
                                    double(GetTimeMillis() - nStartTime))) /
         2;
 
     if (kMasterKey.nDeriveIterations < 25000) {
         kMasterKey.nDeriveIterations = 25000;
     }
 
     WalletLogPrintf("Encrypting Wallet with an nDeriveIterations of %i\n",
                     kMasterKey.nDeriveIterations);
 
     if (!crypter.SetKeyFromPassphrase(strWalletPassphrase, kMasterKey.vchSalt,
                                       kMasterKey.nDeriveIterations,
                                       kMasterKey.nDerivationMethod)) {
         return false;
     }
 
     if (!crypter.Encrypt(_vMasterKey, kMasterKey.vchCryptedKey)) {
         return false;
     }
 
     {
         LOCK(cs_wallet);
         mapMasterKeys[++nMasterKeyMaxID] = kMasterKey;
         WalletBatch *encrypted_batch = new WalletBatch(*database);
         if (!encrypted_batch->TxnBegin()) {
             delete encrypted_batch;
             encrypted_batch = nullptr;
             return false;
         }
         encrypted_batch->WriteMasterKey(nMasterKeyMaxID, kMasterKey);
 
         for (const auto &spk_man_pair : m_spk_managers) {
             auto spk_man = spk_man_pair.second.get();
             if (!spk_man->Encrypt(_vMasterKey, encrypted_batch)) {
                 encrypted_batch->TxnAbort();
                 delete encrypted_batch;
                 encrypted_batch = nullptr;
                 // We now probably have half of our keys encrypted in memory,
                 // and half not... die and let the user reload the unencrypted
                 // wallet.
                 assert(false);
             }
         }
 
         // Encryption was introduced in version 0.4.0
         SetMinVersion(FEATURE_WALLETCRYPT, encrypted_batch, true);
 
         if (!encrypted_batch->TxnCommit()) {
             delete encrypted_batch;
             encrypted_batch = nullptr;
             // We now have keys encrypted in memory, but not on disk...
             // die to avoid confusion and let the user reload the unencrypted
             // wallet.
             assert(false);
         }
 
         delete encrypted_batch;
         encrypted_batch = nullptr;
 
         Lock();
         Unlock(strWalletPassphrase);
 
         // If we are using descriptors, make new descriptors with a new seed
         if (IsWalletFlagSet(WALLET_FLAG_DESCRIPTORS) &&
             !IsWalletFlagSet(WALLET_FLAG_BLANK_WALLET)) {
             SetupDescriptorScriptPubKeyMans();
         } else if (auto spk_man = GetLegacyScriptPubKeyMan()) {
             // if we are using HD, replace the HD seed with a new one
             if (spk_man->IsHDEnabled()) {
                 if (!spk_man->SetupGeneration(true)) {
                     return false;
                 }
             }
         }
         Lock();
 
         // Need to completely rewrite the wallet file; if we don't, bdb might
         // keep bits of the unencrypted private key in slack space in the
         // database file.
         database->Rewrite();
 
         // BDB seems to have a bad habit of writing old data into
         // slack space in .dat files; that is bad if the old data is
         // unencrypted private keys. So:
         database->ReloadDbEnv();
     }
 
     NotifyStatusChanged(this);
     return true;
 }
 
 DBErrors CWallet::ReorderTransactions() {
     LOCK(cs_wallet);
     WalletBatch batch(*database);
 
     // Old wallets didn't have any defined order for transactions. Probably a
     // bad idea to change the output of this.
 
     // First: get all CWalletTx into a sorted-by-time
     // multimap.
     TxItems txByTime;
 
     for (auto &entry : mapWallet) {
         CWalletTx *wtx = &entry.second;
         txByTime.insert(std::make_pair(wtx->nTimeReceived, wtx));
     }
 
     nOrderPosNext = 0;
     std::vector<int64_t> nOrderPosOffsets;
     for (TxItems::iterator it = txByTime.begin(); it != txByTime.end(); ++it) {
         CWalletTx *const pwtx = (*it).second;
         int64_t &nOrderPos = pwtx->nOrderPos;
 
         if (nOrderPos == -1) {
             nOrderPos = nOrderPosNext++;
             nOrderPosOffsets.push_back(nOrderPos);
 
             if (!batch.WriteTx(*pwtx)) {
                 return DBErrors::LOAD_FAIL;
             }
         } else {
             int64_t nOrderPosOff = 0;
             for (const int64_t &nOffsetStart : nOrderPosOffsets) {
                 if (nOrderPos >= nOffsetStart) {
                     ++nOrderPosOff;
                 }
             }
 
             nOrderPos += nOrderPosOff;
             nOrderPosNext = std::max(nOrderPosNext, nOrderPos + 1);
 
             if (!nOrderPosOff) {
                 continue;
             }
 
             // Since we're changing the order, write it back.
             if (!batch.WriteTx(*pwtx)) {
                 return DBErrors::LOAD_FAIL;
             }
         }
     }
 
     batch.WriteOrderPosNext(nOrderPosNext);
 
     return DBErrors::LOAD_OK;
 }
 
 int64_t CWallet::IncOrderPosNext(WalletBatch *batch) {
     AssertLockHeld(cs_wallet);
     int64_t nRet = nOrderPosNext++;
     if (batch) {
         batch->WriteOrderPosNext(nOrderPosNext);
     } else {
         WalletBatch(*database).WriteOrderPosNext(nOrderPosNext);
     }
 
     return nRet;
 }
 
 void CWallet::MarkDirty() {
     LOCK(cs_wallet);
     for (std::pair<const TxId, CWalletTx> &item : mapWallet) {
         item.second.MarkDirty();
     }
 }
 
 void CWallet::SetSpentKeyState(WalletBatch &batch, const TxId &txid,
                                unsigned int n, bool used,
                                std::set<CTxDestination> &tx_destinations) {
     AssertLockHeld(cs_wallet);
     const CWalletTx *srctx = GetWalletTx(txid);
     if (!srctx) {
         return;
     }
 
     CTxDestination dst;
     if (ExtractDestination(srctx->tx->vout[n].scriptPubKey, dst)) {
         if (IsMine(dst)) {
             if (used && !GetDestData(dst, "used", nullptr)) {
                 // p for "present", opposite of absent (null)
                 if (AddDestData(batch, dst, "used", "p")) {
                     tx_destinations.insert(dst);
                 }
             } else if (!used && GetDestData(dst, "used", nullptr)) {
                 EraseDestData(batch, dst, "used");
             }
         }
     }
 }
 
 bool CWallet::IsSpentKey(const TxId &txid, unsigned int n) const {
     AssertLockHeld(cs_wallet);
     const CWalletTx *srctx = GetWalletTx(txid);
     if (srctx) {
         assert(srctx->tx->vout.size() > n);
         CTxDestination dest;
         if (!ExtractDestination(srctx->tx->vout[n].scriptPubKey, dest)) {
             return false;
         }
         if (GetDestData(dest, "used", nullptr)) {
             return true;
         }
         if (IsLegacy()) {
             LegacyScriptPubKeyMan *spk_man = GetLegacyScriptPubKeyMan();
             assert(spk_man != nullptr);
             for (const auto &keyid :
                  GetAffectedKeys(srctx->tx->vout[n].scriptPubKey, *spk_man)) {
                 PKHash pkh_dest(keyid);
                 if (GetDestData(pkh_dest, "used", nullptr)) {
                     return true;
                 }
             }
         }
     }
     return false;
 }
 
 CWalletTx *CWallet::AddToWallet(CTransactionRef tx,
                                 const CWalletTx::Confirmation &confirm,
                                 const UpdateWalletTxFn &update_wtx,
                                 bool fFlushOnClose) {
     LOCK(cs_wallet);
 
     WalletBatch batch(*database, "r+", fFlushOnClose);
 
     const TxId &txid = tx->GetId();
 
     if (IsWalletFlagSet(WALLET_FLAG_AVOID_REUSE)) {
         // Mark used destinations
         std::set<CTxDestination> tx_destinations;
 
         for (const CTxIn &txin : tx->vin) {
             const COutPoint &op = txin.prevout;
             SetSpentKeyState(batch, op.GetTxId(), op.GetN(), true,
                              tx_destinations);
         }
 
         MarkDestinationsDirty(tx_destinations);
     }
 
     // Inserts only if not already there, returns tx inserted or tx found.
     auto ret =
         mapWallet.emplace(std::piecewise_construct, std::forward_as_tuple(txid),
                           std::forward_as_tuple(this, tx));
     CWalletTx &wtx = (*ret.first).second;
     bool fInsertedNew = ret.second;
     bool fUpdated = update_wtx && update_wtx(wtx, fInsertedNew);
     if (fInsertedNew) {
         wtx.m_confirm = confirm;
         wtx.nTimeReceived = chain().getAdjustedTime();
         wtx.nOrderPos = IncOrderPosNext(&batch);
         wtx.m_it_wtxOrdered =
             wtxOrdered.insert(std::make_pair(wtx.nOrderPos, &wtx));
         wtx.nTimeSmart = ComputeTimeSmart(wtx);
         AddToSpends(txid);
     }
 
     if (!fInsertedNew) {
         if (confirm.status != wtx.m_confirm.status) {
             wtx.m_confirm.status = confirm.status;
             wtx.m_confirm.nIndex = confirm.nIndex;
             wtx.m_confirm.hashBlock = confirm.hashBlock;
             wtx.m_confirm.block_height = confirm.block_height;
             fUpdated = true;
         } else {
             assert(wtx.m_confirm.nIndex == confirm.nIndex);
             assert(wtx.m_confirm.hashBlock == confirm.hashBlock);
             assert(wtx.m_confirm.block_height == confirm.block_height);
         }
     }
 
     //// debug print
     WalletLogPrintf("AddToWallet %s  %s%s\n", txid.ToString(),
                     (fInsertedNew ? "new" : ""), (fUpdated ? "update" : ""));
 
     // Write to disk
     if ((fInsertedNew || fUpdated) && !batch.WriteTx(wtx)) {
         return nullptr;
     }
 
     // Break debit/credit balance caches:
     wtx.MarkDirty();
 
     // Notify UI of new or updated transaction.
     NotifyTransactionChanged(this, txid, fInsertedNew ? CT_NEW : CT_UPDATED);
 
 #if defined(HAVE_SYSTEM)
     // Notify an external script when a wallet transaction comes in or is
     // updated.
     std::string strCmd = gArgs.GetArg("-walletnotify", "");
 
     if (!strCmd.empty()) {
         boost::replace_all(strCmd, "%s", txid.GetHex());
 #ifndef WIN32
         // Substituting the wallet name isn't currently supported on windows
         // because windows shell escaping has not been implemented yet:
         // https://github.com/bitcoin/bitcoin/pull/13339#issuecomment-537384875
         // A few ways it could be implemented in the future are described in:
         // https://github.com/bitcoin/bitcoin/pull/13339#issuecomment-461288094
         boost::replace_all(strCmd, "%w", ShellEscape(GetName()));
 #endif
 
         std::thread t(runCommand, strCmd);
         // Thread runs free.
         t.detach();
     }
 #endif
 
     return &wtx;
 }
 
 bool CWallet::LoadToWallet(const TxId &txid, const UpdateWalletTxFn &fill_wtx) {
     const auto &ins =
         mapWallet.emplace(std::piecewise_construct, std::forward_as_tuple(txid),
                           std::forward_as_tuple(this, nullptr));
     CWalletTx &wtx = ins.first->second;
     if (!fill_wtx(wtx, ins.second)) {
         return false;
     }
     // If wallet doesn't have a chain (e.g wallet-tool), don't bother to update
     // txn.
     if (HaveChain()) {
         std::optional<int> block_height =
             chain().getBlockHeight(wtx.m_confirm.hashBlock);
         if (block_height) {
             // Update cached block height variable since it not stored in the
             // serialized transaction.
             wtx.m_confirm.block_height = *block_height;
         } else if (wtx.isConflicted() || wtx.isConfirmed()) {
             // If tx block (or conflicting block) was reorged out of chain
             // while the wallet was shutdown, change tx status to UNCONFIRMED
             // and reset block height, hash, and index. ABANDONED tx don't have
             // associated blocks and don't need to be updated. The case where a
             // transaction was reorged out while online and then reconfirmed
             // while offline is covered by the rescan logic.
             wtx.setUnconfirmed();
             wtx.m_confirm.hashBlock = BlockHash();
             wtx.m_confirm.block_height = 0;
             wtx.m_confirm.nIndex = 0;
         }
     }
     if (/* insertion took place */ ins.second) {
         wtx.m_it_wtxOrdered =
             wtxOrdered.insert(std::make_pair(wtx.nOrderPos, &wtx));
     }
     AddToSpends(txid);
     for (const CTxIn &txin : wtx.tx->vin) {
         auto it = mapWallet.find(txin.prevout.GetTxId());
         if (it != mapWallet.end()) {
             CWalletTx &prevtx = it->second;
             if (prevtx.isConflicted()) {
                 MarkConflicted(prevtx.m_confirm.hashBlock,
                                prevtx.m_confirm.block_height, wtx.GetId());
             }
         }
     }
     return true;
 }
 
 bool CWallet::AddToWalletIfInvolvingMe(const CTransactionRef &ptx,
                                        CWalletTx::Confirmation confirm,
                                        bool fUpdate) {
     const CTransaction &tx = *ptx;
     AssertLockHeld(cs_wallet);
 
     if (!confirm.hashBlock.IsNull()) {
         for (const CTxIn &txin : tx.vin) {
             std::pair<TxSpends::const_iterator, TxSpends::const_iterator>
                 range = mapTxSpends.equal_range(txin.prevout);
             while (range.first != range.second) {
                 if (range.first->second != tx.GetId()) {
                     WalletLogPrintf(
                         "Transaction %s (in block %s) conflicts with wallet "
                         "transaction %s (both spend %s:%i)\n",
                         tx.GetId().ToString(), confirm.hashBlock.ToString(),
                         range.first->second.ToString(),
                         range.first->first.GetTxId().ToString(),
                         range.first->first.GetN());
                     MarkConflicted(confirm.hashBlock, confirm.block_height,
                                    range.first->second);
                 }
                 range.first++;
             }
         }
     }
 
     bool fExisted = mapWallet.count(tx.GetId()) != 0;
     if (fExisted && !fUpdate) {
         return false;
     }
     if (fExisted || IsMine(tx) || IsFromMe(tx)) {
         /**
          * Check if any keys in the wallet keypool that were supposed to be
          * unused have appeared in a new transaction. If so, remove those keys
          * from the keypool. This can happen when restoring an old wallet backup
          * that does not contain the mostly recently created transactions from
          * newer versions of the wallet.
          */
 
         // loop though all outputs
         for (const CTxOut &txout : tx.vout) {
             for (const auto &spk_man_pair : m_spk_managers) {
                 spk_man_pair.second->MarkUnusedAddresses(txout.scriptPubKey);
             }
         }
 
         // Block disconnection override an abandoned tx as unconfirmed
         // which means user may have to call abandontransaction again
         return AddToWallet(MakeTransactionRef(tx), confirm,
                            /* update_wtx= */ nullptr,
                            /* fFlushOnClose= */ false);
     }
     return false;
 }
 
 bool CWallet::TransactionCanBeAbandoned(const TxId &txid) const {
     LOCK(cs_wallet);
     const CWalletTx *wtx = GetWalletTx(txid);
     return wtx && !wtx->isAbandoned() && wtx->GetDepthInMainChain() == 0 &&
            !wtx->InMempool();
 }
 
 void CWallet::MarkInputsDirty(const CTransactionRef &tx) {
     for (const CTxIn &txin : tx->vin) {
         auto it = mapWallet.find(txin.prevout.GetTxId());
         if (it != mapWallet.end()) {
             it->second.MarkDirty();
         }
     }
 }
 
 bool CWallet::AbandonTransaction(const TxId &txid) {
     LOCK(cs_wallet);
 
     WalletBatch batch(*database, "r+");
 
     std::set<TxId> todo;
     std::set<TxId> done;
 
     // Can't mark abandoned if confirmed or in mempool
     auto it = mapWallet.find(txid);
     assert(it != mapWallet.end());
     CWalletTx &origtx = it->second;
     if (origtx.GetDepthInMainChain() != 0 || origtx.InMempool()) {
         return false;
     }
 
     todo.insert(txid);
 
     while (!todo.empty()) {
         const TxId now = *todo.begin();
         todo.erase(now);
         done.insert(now);
         it = mapWallet.find(now);
         assert(it != mapWallet.end());
         CWalletTx &wtx = it->second;
         int currentconfirm = wtx.GetDepthInMainChain();
         // If the orig tx was not in block, none of its spends can be.
         assert(currentconfirm <= 0);
         // If (currentconfirm < 0) {Tx and spends are already conflicted, no
         // need to abandon}
         if (currentconfirm == 0 && !wtx.isAbandoned()) {
             // If the orig tx was not in block/mempool, none of its spends can
             // be in mempool.
             assert(!wtx.InMempool());
             wtx.setAbandoned();
             wtx.MarkDirty();
             batch.WriteTx(wtx);
             NotifyTransactionChanged(this, wtx.GetId(), CT_UPDATED);
             // Iterate over all its outputs, and mark transactions in the wallet
             // that spend them abandoned too.
             TxSpends::const_iterator iter =
                 mapTxSpends.lower_bound(COutPoint(now, 0));
             while (iter != mapTxSpends.end() && iter->first.GetTxId() == now) {
                 if (!done.count(iter->second)) {
                     todo.insert(iter->second);
                 }
                 iter++;
             }
 
             // If a transaction changes 'conflicted' state, that changes the
             // balance available of the outputs it spends. So force those to be
             // recomputed.
             MarkInputsDirty(wtx.tx);
         }
     }
 
     return true;
 }
 
 void CWallet::MarkConflicted(const BlockHash &hashBlock, int conflicting_height,
                              const TxId &txid) {
     LOCK(cs_wallet);
 
     int conflictconfirms =
         (m_last_block_processed_height - conflicting_height + 1) * -1;
 
     // If number of conflict confirms cannot be determined, this means that the
     // block is still unknown or not yet part of the main chain, for example
     // when loading the wallet during a reindex. Do nothing in that case.
     if (conflictconfirms >= 0) {
         return;
     }
 
     // Do not flush the wallet here for performance reasons.
     WalletBatch batch(*database, "r+", false);
 
     std::set<TxId> todo;
     std::set<TxId> done;
 
     todo.insert(txid);
 
     while (!todo.empty()) {
         const TxId now = *todo.begin();
         todo.erase(now);
         done.insert(now);
         auto it = mapWallet.find(now);
         assert(it != mapWallet.end());
         CWalletTx &wtx = it->second;
         int currentconfirm = wtx.GetDepthInMainChain();
         if (conflictconfirms < currentconfirm) {
             // Block is 'more conflicted' than current confirm; update.
             // Mark transaction as conflicted with this block.
             wtx.m_confirm.nIndex = 0;
             wtx.m_confirm.hashBlock = hashBlock;
             wtx.m_confirm.block_height = conflicting_height;
             wtx.setConflicted();
             wtx.MarkDirty();
             batch.WriteTx(wtx);
             // Iterate over all its outputs, and mark transactions in the wallet
             // that spend them conflicted too.
             TxSpends::const_iterator iter =
                 mapTxSpends.lower_bound(COutPoint(now, 0));
             while (iter != mapTxSpends.end() && iter->first.GetTxId() == now) {
                 if (!done.count(iter->second)) {
                     todo.insert(iter->second);
                 }
                 iter++;
             }
             // If a transaction changes 'conflicted' state, that changes the
             // balance available of the outputs it spends. So force those to be
             // recomputed.
             MarkInputsDirty(wtx.tx);
         }
     }
 }
 
 void CWallet::SyncTransaction(const CTransactionRef &ptx,
                               CWalletTx::Confirmation confirm, bool update_tx) {
     if (!AddToWalletIfInvolvingMe(ptx, confirm, update_tx)) {
         // Not one of ours
         return;
     }
 
     // If a transaction changes 'conflicted' state, that changes the balance
     // available of the outputs it spends. So force those to be
     // recomputed, also:
     MarkInputsDirty(ptx);
 }
 
-void CWallet::transactionAddedToMempool(const CTransactionRef &tx) {
+void CWallet::transactionAddedToMempool(const CTransactionRef &tx,
+                                        uint64_t mempool_sequence) {
     LOCK(cs_wallet);
 
     SyncTransaction(tx, {CWalletTx::Status::UNCONFIRMED, /* block_height */ 0,
                          BlockHash(), /* nIndex */ 0});
 
     auto it = mapWallet.find(tx->GetId());
     if (it != mapWallet.end()) {
         it->second.fInMempool = true;
     }
 }
 
 void CWallet::transactionRemovedFromMempool(const CTransactionRef &tx,
-                                            MemPoolRemovalReason reason) {
+                                            MemPoolRemovalReason reason,
+                                            uint64_t mempool_sequence) {
     LOCK(cs_wallet);
     auto it = mapWallet.find(tx->GetId());
     if (it != mapWallet.end()) {
         it->second.fInMempool = false;
     }
     // Handle transactions that were removed from the mempool because they
     // conflict with transactions in a newly connected block.
     if (reason == MemPoolRemovalReason::CONFLICT) {
         // Call SyncNotifications, so external -walletnotify notifications will
         // be triggered for these transactions. Set Status::UNCONFIRMED instead
         // of Status::CONFLICTED for a few reasons:
         //
         // 1. The transactionRemovedFromMempool callback does not currently
         //    provide the conflicting block's hash and height, and for backwards
         //    compatibility reasons it may not be not safe to store conflicted
         //    wallet transactions with a null block hash. See
         //    https://github.com/bitcoin/bitcoin/pull/18600#discussion_r420195993.
         // 2. For most of these transactions, the wallet's internal conflict
         //    detection in the blockConnected handler will subsequently call
         //    MarkConflicted and update them with CONFLICTED status anyway. This
         //    applies to any wallet transaction that has inputs spent in the
         //    block, or that has ancestors in the wallet with inputs spent by
         //    the block.
         // 3. Longstanding behavior since the sync implementation in
         //    https://github.com/bitcoin/bitcoin/pull/9371 and the prior sync
         //    implementation before that was to mark these transactions
         //    unconfirmed rather than conflicted.
         //
         // Nothing described above should be seen as an unchangeable requirement
         // when improving this code in the future. The wallet's heuristics for
         // distinguishing between conflicted and unconfirmed transactions are
         // imperfect, and could be improved in general, see
         // https://github.com/bitcoin-core/bitcoin-devwiki/wiki/Wallet-Transaction-Conflict-Tracking
         SyncTransaction(tx,
                         {CWalletTx::Status::UNCONFIRMED, /* block height  */ 0,
                          BlockHash(), /* index */ 0});
     }
 }
 
 void CWallet::blockConnected(const CBlock &block, int height) {
     const BlockHash &block_hash = block.GetHash();
     LOCK(cs_wallet);
 
     m_last_block_processed_height = height;
     m_last_block_processed = block_hash;
     for (size_t index = 0; index < block.vtx.size(); index++) {
         SyncTransaction(block.vtx[index], {CWalletTx::Status::CONFIRMED, height,
                                            block_hash, int(index)});
         transactionRemovedFromMempool(block.vtx[index],
-                                      MemPoolRemovalReason::BLOCK);
+                                      MemPoolRemovalReason::BLOCK,
+                                      0 /* mempool_sequence */);
     }
 }
 
 void CWallet::blockDisconnected(const CBlock &block, int height) {
     LOCK(cs_wallet);
 
     // At block disconnection, this will change an abandoned transaction to
     // be unconfirmed, whether or not the transaction is added back to the
     // mempool. User may have to call abandontransaction again. It may be
     // addressed in the future with a stickier abandoned state or even removing
     // abandontransaction call.
     m_last_block_processed_height = height - 1;
     m_last_block_processed = block.hashPrevBlock;
     for (const CTransactionRef &ptx : block.vtx) {
         SyncTransaction(ptx,
                         {CWalletTx::Status::UNCONFIRMED, /* block_height */ 0,
                          BlockHash(), /* nIndex */ 0});
     }
 }
 
 void CWallet::updatedBlockTip() {
     m_best_block_time = GetTime();
 }
 
 void CWallet::BlockUntilSyncedToCurrentChain() const {
     AssertLockNotHeld(cs_wallet);
     // Skip the queue-draining stuff if we know we're caught up with
     // chainActive.Tip(), otherwise put a callback in the validation interface
     // queue and wait for the queue to drain enough to execute it (indicating we
     // are caught up at least with the time we entered this function).
     const BlockHash last_block_hash =
         WITH_LOCK(cs_wallet, return m_last_block_processed);
     chain().waitForNotificationsIfTipChanged(last_block_hash);
 }
 
 isminetype CWallet::IsMine(const CTxIn &txin) const {
     AssertLockHeld(cs_wallet);
     std::map<TxId, CWalletTx>::const_iterator mi =
         mapWallet.find(txin.prevout.GetTxId());
     if (mi != mapWallet.end()) {
         const CWalletTx &prev = (*mi).second;
         if (txin.prevout.GetN() < prev.tx->vout.size()) {
             return IsMine(prev.tx->vout[txin.prevout.GetN()]);
         }
     }
 
     return ISMINE_NO;
 }
 
 // Note that this function doesn't distinguish between a 0-valued input, and a
 // not-"is mine" (according to the filter) input.
 Amount CWallet::GetDebit(const CTxIn &txin, const isminefilter &filter) const {
     LOCK(cs_wallet);
     std::map<TxId, CWalletTx>::const_iterator mi =
         mapWallet.find(txin.prevout.GetTxId());
     if (mi != mapWallet.end()) {
         const CWalletTx &prev = (*mi).second;
         if (txin.prevout.GetN() < prev.tx->vout.size()) {
             if (IsMine(prev.tx->vout[txin.prevout.GetN()]) & filter) {
                 return prev.tx->vout[txin.prevout.GetN()].nValue;
             }
         }
     }
 
     return Amount::zero();
 }
 
 isminetype CWallet::IsMine(const CTxOut &txout) const {
     AssertLockHeld(cs_wallet);
     return IsMine(txout.scriptPubKey);
 }
 
 isminetype CWallet::IsMine(const CTxDestination &dest) const {
     AssertLockHeld(cs_wallet);
     return IsMine(GetScriptForDestination(dest));
 }
 
 isminetype CWallet::IsMine(const CScript &script) const {
     AssertLockHeld(cs_wallet);
     isminetype result = ISMINE_NO;
     for (const auto &spk_man_pair : m_spk_managers) {
         result = std::max(result, spk_man_pair.second->IsMine(script));
     }
     return result;
 }
 
 Amount CWallet::GetCredit(const CTxOut &txout,
                           const isminefilter &filter) const {
     if (!MoneyRange(txout.nValue)) {
         throw std::runtime_error(std::string(__func__) +
                                  ": value out of range");
     }
     LOCK(cs_wallet);
     return (IsMine(txout) & filter) ? txout.nValue : Amount::zero();
 }
 
 bool CWallet::IsChange(const CTxOut &txout) const {
     return IsChange(txout.scriptPubKey);
 }
 
 bool CWallet::IsChange(const CScript &script) const {
     // TODO: fix handling of 'change' outputs. The assumption is that any
     // payment to a script that is ours, but is not in the address book is
     // change. That assumption is likely to break when we implement
     // multisignature wallets that return change back into a
     // multi-signature-protected address; a better way of identifying which
     // outputs are 'the send' and which are 'the change' will need to be
     // implemented (maybe extend CWalletTx to remember which output, if any, was
     // change).
     AssertLockHeld(cs_wallet);
     if (IsMine(script)) {
         CTxDestination address;
         if (!ExtractDestination(script, address)) {
             return true;
         }
         if (!FindAddressBookEntry(address)) {
             return true;
         }
     }
 
     return false;
 }
 
 Amount CWallet::GetChange(const CTxOut &txout) const {
     AssertLockHeld(cs_wallet);
     if (!MoneyRange(txout.nValue)) {
         throw std::runtime_error(std::string(__func__) +
                                  ": value out of range");
     }
 
     return (IsChange(txout) ? txout.nValue : Amount::zero());
 }
 
 bool CWallet::IsMine(const CTransaction &tx) const {
     AssertLockHeld(cs_wallet);
     for (const CTxOut &txout : tx.vout) {
         if (IsMine(txout)) {
             return true;
         }
     }
 
     return false;
 }
 
 bool CWallet::IsFromMe(const CTransaction &tx) const {
     return GetDebit(tx, ISMINE_ALL) > Amount::zero();
 }
 
 Amount CWallet::GetDebit(const CTransaction &tx,
                          const isminefilter &filter) const {
     Amount nDebit = Amount::zero();
     for (const CTxIn &txin : tx.vin) {
         nDebit += GetDebit(txin, filter);
         if (!MoneyRange(nDebit)) {
             throw std::runtime_error(std::string(__func__) +
                                      ": value out of range");
         }
     }
 
     return nDebit;
 }
 
 bool CWallet::IsAllFromMe(const CTransaction &tx,
                           const isminefilter &filter) const {
     LOCK(cs_wallet);
 
     for (const CTxIn &txin : tx.vin) {
         auto mi = mapWallet.find(txin.prevout.GetTxId());
         if (mi == mapWallet.end()) {
             // Any unknown inputs can't be from us.
             return false;
         }
 
         const CWalletTx &prev = (*mi).second;
 
         if (txin.prevout.GetN() >= prev.tx->vout.size()) {
             // Invalid input!
             return false;
         }
 
         if (!(IsMine(prev.tx->vout[txin.prevout.GetN()]) & filter)) {
             return false;
         }
     }
 
     return true;
 }
 
 Amount CWallet::GetCredit(const CTransaction &tx,
                           const isminefilter &filter) const {
     Amount nCredit = Amount::zero();
     for (const CTxOut &txout : tx.vout) {
         nCredit += GetCredit(txout, filter);
         if (!MoneyRange(nCredit)) {
             throw std::runtime_error(std::string(__func__) +
                                      ": value out of range");
         }
     }
 
     return nCredit;
 }
 
 Amount CWallet::GetChange(const CTransaction &tx) const {
     LOCK(cs_wallet);
     Amount nChange = Amount::zero();
     for (const CTxOut &txout : tx.vout) {
         nChange += GetChange(txout);
         if (!MoneyRange(nChange)) {
             throw std::runtime_error(std::string(__func__) +
                                      ": value out of range");
         }
     }
 
     return nChange;
 }
 
 bool CWallet::IsHDEnabled() const {
     // All Active ScriptPubKeyMans must be HD for this to be true
     bool result = true;
     for (const auto &spk_man : GetActiveScriptPubKeyMans()) {
         result &= spk_man->IsHDEnabled();
     }
     return result;
 }
 
 bool CWallet::CanGetAddresses(bool internal) const {
     LOCK(cs_wallet);
     if (m_spk_managers.empty()) {
         return false;
     }
     for (OutputType t : OUTPUT_TYPES) {
         auto spk_man = GetScriptPubKeyMan(t, internal);
         if (spk_man && spk_man->CanGetAddresses(internal)) {
             return true;
         }
     }
     return false;
 }
 
 void CWallet::SetWalletFlag(uint64_t flags) {
     LOCK(cs_wallet);
     m_wallet_flags |= flags;
     if (!WalletBatch(*database).WriteWalletFlags(m_wallet_flags)) {
         throw std::runtime_error(std::string(__func__) +
                                  ": writing wallet flags failed");
     }
 }
 
 void CWallet::UnsetWalletFlag(uint64_t flag) {
     WalletBatch batch(*database);
     UnsetWalletFlagWithDB(batch, flag);
 }
 
 void CWallet::UnsetWalletFlagWithDB(WalletBatch &batch, uint64_t flag) {
     LOCK(cs_wallet);
     m_wallet_flags &= ~flag;
     if (!batch.WriteWalletFlags(m_wallet_flags)) {
         throw std::runtime_error(std::string(__func__) +
                                  ": writing wallet flags failed");
     }
 }
 
 void CWallet::UnsetBlankWalletFlag(WalletBatch &batch) {
     UnsetWalletFlagWithDB(batch, WALLET_FLAG_BLANK_WALLET);
 }
 
 bool CWallet::IsWalletFlagSet(uint64_t flag) const {
     return (m_wallet_flags & flag);
 }
 
 bool CWallet::LoadWalletFlags(uint64_t flags) {
     LOCK(cs_wallet);
     if (((flags & KNOWN_WALLET_FLAGS) >> 32) ^ (flags >> 32)) {
         // contains unknown non-tolerable wallet flags
         return false;
     }
     m_wallet_flags = flags;
 
     return true;
 }
 
 bool CWallet::AddWalletFlags(uint64_t flags) {
     LOCK(cs_wallet);
     // We should never be writing unknown non-tolerable wallet flags
     assert(((flags & KNOWN_WALLET_FLAGS) >> 32) == (flags >> 32));
     if (!WalletBatch(*database).WriteWalletFlags(flags)) {
         throw std::runtime_error(std::string(__func__) +
                                  ": writing wallet flags failed");
     }
 
     return LoadWalletFlags(flags);
 }
 
 int64_t CWalletTx::GetTxTime() const {
     int64_t n = nTimeSmart;
     return n ? n : nTimeReceived;
 }
 
 // Helper for producing a max-sized low-S low-R signature (eg 71 bytes)
 // or a max-sized low-S signature (e.g. 72 bytes) if use_max_sig is true
 bool CWallet::DummySignInput(CTxIn &tx_in, const CTxOut &txout,
                              bool use_max_sig) const {
     // Fill in dummy signatures for fee calculation.
     const CScript &scriptPubKey = txout.scriptPubKey;
     SignatureData sigdata;
 
     std::unique_ptr<SigningProvider> provider =
         GetSolvingProvider(scriptPubKey);
     if (!provider) {
         // We don't know about this scriptpbuKey;
         return false;
     }
 
     if (!ProduceSignature(*provider,
                           use_max_sig ? DUMMY_MAXIMUM_SIGNATURE_CREATOR
                                       : DUMMY_SIGNATURE_CREATOR,
                           scriptPubKey, sigdata)) {
         return false;
     }
 
     UpdateInput(tx_in, sigdata);
     return true;
 }
 
 // Helper for producing a bunch of max-sized low-S low-R signatures (eg 71
 // bytes)
 bool CWallet::DummySignTx(CMutableTransaction &txNew,
                           const std::vector<CTxOut> &txouts,
                           bool use_max_sig) const {
     // Fill in dummy signatures for fee calculation.
     int nIn = 0;
     for (const auto &txout : txouts) {
         if (!DummySignInput(txNew.vin[nIn], txout, use_max_sig)) {
             return false;
         }
 
         nIn++;
     }
     return true;
 }
 
 bool CWallet::ImportScripts(const std::set<CScript> scripts,
                             int64_t timestamp) {
     auto spk_man = GetLegacyScriptPubKeyMan();
     if (!spk_man) {
         return false;
     }
     LOCK(spk_man->cs_KeyStore);
     return spk_man->ImportScripts(scripts, timestamp);
 }
 
 bool CWallet::ImportPrivKeys(const std::map<CKeyID, CKey> &privkey_map,
                              const int64_t timestamp) {
     auto spk_man = GetLegacyScriptPubKeyMan();
     if (!spk_man) {
         return false;
     }
     LOCK(spk_man->cs_KeyStore);
     return spk_man->ImportPrivKeys(privkey_map, timestamp);
 }
 
 bool CWallet::ImportPubKeys(
     const std::vector<CKeyID> &ordered_pubkeys,
     const std::map<CKeyID, CPubKey> &pubkey_map,
     const std::map<CKeyID, std::pair<CPubKey, KeyOriginInfo>> &key_origins,
     const bool add_keypool, const bool internal, const int64_t timestamp) {
     auto spk_man = GetLegacyScriptPubKeyMan();
     if (!spk_man) {
         return false;
     }
     LOCK(spk_man->cs_KeyStore);
     return spk_man->ImportPubKeys(ordered_pubkeys, pubkey_map, key_origins,
                                   add_keypool, internal, timestamp);
 }
 
 bool CWallet::ImportScriptPubKeys(const std::string &label,
                                   const std::set<CScript> &script_pub_keys,
                                   const bool have_solving_data,
                                   const bool apply_label,
                                   const int64_t timestamp) {
     auto spk_man = GetLegacyScriptPubKeyMan();
     if (!spk_man) {
         return false;
     }
     LOCK(spk_man->cs_KeyStore);
     if (!spk_man->ImportScriptPubKeys(script_pub_keys, have_solving_data,
                                       timestamp)) {
         return false;
     }
     if (apply_label) {
         WalletBatch batch(*database);
         for (const CScript &script : script_pub_keys) {
             CTxDestination dest;
             ExtractDestination(script, dest);
             if (IsValidDestination(dest)) {
                 SetAddressBookWithDB(batch, dest, label, "receive");
             }
         }
     }
     return true;
 }
 
 int64_t CalculateMaximumSignedTxSize(const CTransaction &tx,
                                      const CWallet *wallet, bool use_max_sig) {
     std::vector<CTxOut> txouts;
     for (auto &input : tx.vin) {
         const auto mi = wallet->mapWallet.find(input.prevout.GetTxId());
         // Can not estimate size without knowing the input details
         if (mi == wallet->mapWallet.end()) {
             return -1;
         }
         assert(input.prevout.GetN() < mi->second.tx->vout.size());
         txouts.emplace_back(mi->second.tx->vout[input.prevout.GetN()]);
     }
     return CalculateMaximumSignedTxSize(tx, wallet, txouts, use_max_sig);
 }
 
 // txouts needs to be in the order of tx.vin
 int64_t CalculateMaximumSignedTxSize(const CTransaction &tx,
                                      const CWallet *wallet,
                                      const std::vector<CTxOut> &txouts,
                                      bool use_max_sig) {
     CMutableTransaction txNew(tx);
     if (!wallet->DummySignTx(txNew, txouts, use_max_sig)) {
         return -1;
     }
     return GetSerializeSize(txNew, PROTOCOL_VERSION);
 }
 
 int CalculateMaximumSignedInputSize(const CTxOut &txout, const CWallet *wallet,
                                     bool use_max_sig) {
     CMutableTransaction txn;
     txn.vin.push_back(CTxIn(COutPoint()));
     if (!wallet->DummySignInput(txn.vin[0], txout, use_max_sig)) {
         return -1;
     }
     return GetSerializeSize(txn.vin[0], PROTOCOL_VERSION);
 }
 
 void CWalletTx::GetAmounts(std::list<COutputEntry> &listReceived,
                            std::list<COutputEntry> &listSent, Amount &nFee,
                            const isminefilter &filter) const {
     nFee = Amount::zero();
     listReceived.clear();
     listSent.clear();
 
     // Compute fee:
     Amount nDebit = GetDebit(filter);
     // debit>0 means we signed/sent this transaction.
     if (nDebit > Amount::zero()) {
         Amount nValueOut = tx->GetValueOut();
         nFee = (nDebit - nValueOut);
     }
 
     LOCK(pwallet->cs_wallet);
     // Sent/received.
     for (unsigned int i = 0; i < tx->vout.size(); ++i) {
         const CTxOut &txout = tx->vout[i];
         isminetype fIsMine = pwallet->IsMine(txout);
         // Only need to handle txouts if AT LEAST one of these is true:
         //   1) they debit from us (sent)
         //   2) the output is to us (received)
         if (nDebit > Amount::zero()) {
             // Don't report 'change' txouts
             if (pwallet->IsChange(txout)) {
                 continue;
             }
         } else if (!(fIsMine & filter)) {
             continue;
         }
 
         // In either case, we need to get the destination address.
         CTxDestination address;
 
         if (!ExtractDestination(txout.scriptPubKey, address) &&
             !txout.scriptPubKey.IsUnspendable()) {
             pwallet->WalletLogPrintf("CWalletTx::GetAmounts: Unknown "
                                      "transaction type found, txid %s\n",
                                      this->GetId().ToString());
             address = CNoDestination();
         }
 
         COutputEntry output = {address, txout.nValue, (int)i};
 
         // If we are debited by the transaction, add the output as a "sent"
         // entry.
         if (nDebit > Amount::zero()) {
             listSent.push_back(output);
         }
 
         // If we are receiving the output, add it as a "received" entry.
         if (fIsMine & filter) {
             listReceived.push_back(output);
         }
     }
 }
 
 /**
  * Scan active chain for relevant transactions after importing keys. This should
  * be called whenever new keys are added to the wallet, with the oldest key
  * creation time.
  *
  * @return Earliest timestamp that could be successfully scanned from. Timestamp
  * returned will be higher than startTime if relevant blocks could not be read.
  */
 int64_t CWallet::RescanFromTime(int64_t startTime,
                                 const WalletRescanReserver &reserver,
                                 bool update) {
     // Find starting block. May be null if nCreateTime is greater than the
     // highest blockchain timestamp, in which case there is nothing that needs
     // to be scanned.
     int start_height = 0;
     BlockHash start_block;
     bool start = chain().findFirstBlockWithTimeAndHeight(
         startTime - TIMESTAMP_WINDOW, 0,
         FoundBlock().hash(start_block).height(start_height));
     WalletLogPrintf("%s: Rescanning last %i blocks\n", __func__,
                     start ? WITH_LOCK(cs_wallet, return GetLastBlockHeight()) -
                                 start_height + 1
                           : 0);
 
     if (start) {
         // TODO: this should take into account failure by ScanResult::USER_ABORT
         ScanResult result = ScanForWalletTransactions(
             start_block, start_height, {} /* max_height */, reserver, update);
         if (result.status == ScanResult::FAILURE) {
             int64_t time_max;
             CHECK_NONFATAL(chain().findBlock(result.last_failed_block,
                                              FoundBlock().maxTime(time_max)));
             return time_max + TIMESTAMP_WINDOW + 1;
         }
     }
     return startTime;
 }
 
 /**
  * Scan the block chain (starting in start_block) for transactions from or to
  * us. If fUpdate is true, found transactions that already exist in the wallet
  * will be updated.
  *
  * @param[in] start_block Scan starting block. If block is not on the active
  *                        chain, the scan will return SUCCESS immediately.
  * @param[in] start_height Height of start_block
  * @param[in] max_height  Optional max scanning height. If unset there is
  *                        no maximum and scanning can continue to the tip
  *
  * @return ScanResult returning scan information and indicating success or
  *         failure. Return status will be set to SUCCESS if scan was
  *         successful. FAILURE if a complete rescan was not possible (due to
  *         pruning or corruption). USER_ABORT if the rescan was aborted before
  *         it could complete.
  *
  * @pre Caller needs to make sure start_block (and the optional stop_block) are
  * on the main chain after to the addition of any new keys you want to detect
  * transactions for.
  */
 CWallet::ScanResult CWallet::ScanForWalletTransactions(
     const BlockHash &start_block, int start_height,
     std::optional<int> max_height, const WalletRescanReserver &reserver,
     bool fUpdate) {
     int64_t nNow = GetTime();
     int64_t start_time = GetTimeMillis();
 
     assert(reserver.isReserved());
 
     BlockHash block_hash = start_block;
     ScanResult result;
 
     WalletLogPrintf("Rescan started from block %s...\n",
                     start_block.ToString());
 
     fAbortRescan = false;
     // Show rescan progress in GUI as dialog or on splashscreen, if -rescan on
     // startup.
     ShowProgress(
         strprintf("%s " + _("Rescanning...").translated, GetDisplayName()), 0);
     BlockHash tip_hash = WITH_LOCK(cs_wallet, return GetLastBlockHash());
     BlockHash end_hash = tip_hash;
     if (max_height) {
         chain().findAncestorByHeight(tip_hash, *max_height,
                                      FoundBlock().hash(end_hash));
     }
     double progress_begin = chain().guessVerificationProgress(block_hash);
     double progress_end = chain().guessVerificationProgress(end_hash);
     double progress_current = progress_begin;
     int block_height = start_height;
     while (!fAbortRescan && !chain().shutdownRequested()) {
         if (progress_end - progress_begin > 0.0) {
             m_scanning_progress = (progress_current - progress_begin) /
                                   (progress_end - progress_begin);
         } else {
             // avoid divide-by-zero for single block scan range (i.e. start and
             // stop hashes are equal)
             m_scanning_progress = 0;
         }
         if (block_height % 100 == 0 && progress_end - progress_begin > 0.0) {
             ShowProgress(
                 strprintf("%s " + _("Rescanning...").translated,
                           GetDisplayName()),
                 std::max(1, std::min(99, (int)(m_scanning_progress * 100))));
         }
         if (GetTime() >= nNow + 60) {
             nNow = GetTime();
             WalletLogPrintf("Still rescanning. At block %d. Progress=%f\n",
                             block_height, progress_current);
         }
 
         CBlock block;
         bool next_block;
         BlockHash next_block_hash;
         bool reorg = false;
         if (chain().findBlock(block_hash, FoundBlock().data(block)) &&
             !block.IsNull()) {
             LOCK(cs_wallet);
             next_block = chain().findNextBlock(
                 block_hash, block_height, FoundBlock().hash(next_block_hash),
                 &reorg);
             if (reorg) {
                 // Abort scan if current block is no longer active, to prevent
                 // marking transactions as coming from the wrong block.
                 // TODO: This should return success instead of failure, see
                 // https://github.com/bitcoin/bitcoin/pull/14711#issuecomment-458342518
                 result.last_failed_block = block_hash;
                 result.status = ScanResult::FAILURE;
                 break;
             }
             for (size_t posInBlock = 0; posInBlock < block.vtx.size();
                  ++posInBlock) {
                 CWalletTx::Confirmation confirm(CWalletTx::Status::CONFIRMED,
                                                 block_height, block_hash,
                                                 posInBlock);
                 SyncTransaction(block.vtx[posInBlock],
                                 {CWalletTx::Status::CONFIRMED, block_height,
                                  block_hash, int(posInBlock)},
                                 fUpdate);
             }
             // scan succeeded, record block as most recent successfully
             // scanned
             result.last_scanned_block = block_hash;
             result.last_scanned_height = block_height;
         } else {
             // could not scan block, keep scanning but record this block as
             // the most recent failure
             result.last_failed_block = block_hash;
             result.status = ScanResult::FAILURE;
             next_block = chain().findNextBlock(
                 block_hash, block_height, FoundBlock().hash(next_block_hash),
                 &reorg);
         }
         if (max_height && block_height >= *max_height) {
             break;
         }
         {
             if (!next_block || reorg) {
                 // break successfully when rescan has reached the tip, or
                 // previous block is no longer on the chain due to a reorg
                 break;
             }
 
             // increment block and verification progress
             block_hash = next_block_hash;
             ++block_height;
             progress_current = chain().guessVerificationProgress(block_hash);
 
             // handle updated tip hash
             const BlockHash prev_tip_hash = tip_hash;
             tip_hash = WITH_LOCK(cs_wallet, return GetLastBlockHash());
             if (!max_height && prev_tip_hash != tip_hash) {
                 // in case the tip has changed, update progress max
                 progress_end = chain().guessVerificationProgress(tip_hash);
             }
         }
     }
 
     // Hide progress dialog in GUI.
     ShowProgress(
         strprintf("%s " + _("Rescanning...").translated, GetDisplayName()),
         100);
     if (block_height && fAbortRescan) {
         WalletLogPrintf("Rescan aborted at block %d. Progress=%f\n",
                         block_height, progress_current);
         result.status = ScanResult::USER_ABORT;
     } else if (block_height && chain().shutdownRequested()) {
         WalletLogPrintf(
             "Rescan interrupted by shutdown request at block %d. Progress=%f\n",
             block_height, progress_current);
         result.status = ScanResult::USER_ABORT;
     } else {
         WalletLogPrintf("Rescan completed in %15dms\n",
                         GetTimeMillis() - start_time);
     }
     return result;
 }
 
 void CWallet::ReacceptWalletTransactions() {
     // If transactions aren't being broadcasted, don't let them into local
     // mempool either.
     if (!fBroadcastTransactions) {
         return;
     }
 
     std::map<int64_t, CWalletTx *> mapSorted;
 
     // Sort pending wallet transactions based on their initial wallet insertion
     // order.
     for (std::pair<const TxId, CWalletTx> &item : mapWallet) {
         const TxId &wtxid = item.first;
         CWalletTx &wtx = item.second;
         assert(wtx.GetId() == wtxid);
 
         int nDepth = wtx.GetDepthInMainChain();
 
         if (!wtx.IsCoinBase() && (nDepth == 0 && !wtx.isAbandoned())) {
             mapSorted.insert(std::make_pair(wtx.nOrderPos, &wtx));
         }
     }
 
     // Try to add wallet transactions to memory pool.
     for (const std::pair<const int64_t, CWalletTx *> &item : mapSorted) {
         CWalletTx &wtx = *(item.second);
         std::string unused_err_string;
         wtx.SubmitMemoryPoolAndRelay(unused_err_string, false);
     }
 }
 
 bool CWalletTx::SubmitMemoryPoolAndRelay(std::string &err_string, bool relay) {
     // Can't relay if wallet is not broadcasting
     if (!pwallet->GetBroadcastTransactions()) {
         return false;
     }
     // Don't relay abandoned transactions
     if (isAbandoned()) {
         return false;
     }
     // Don't try to submit coinbase transactions. These would fail anyway but
     // would cause log spam.
     if (IsCoinBase()) {
         return false;
     }
     // Don't try to submit conflicted or confirmed transactions.
     if (GetDepthInMainChain() != 0) {
         return false;
     }
 
     // Submit transaction to mempool for relay
     pwallet->WalletLogPrintf("Submitting wtx %s to mempool for relay\n",
                              GetId().ToString());
     // We must set fInMempool here - while it will be re-set to true by the
     // entered-mempool callback, if we did not there would be a race where a
     // user could call sendmoney in a loop and hit spurious out of funds errors
     // because we think that this newly generated transaction's change is
     // unavailable as we're not yet aware that it is in the mempool.
     //
     // Irrespective of the failure reason, un-marking fInMempool
     // out-of-order is incorrect - it should be unmarked when
     // TransactionRemovedFromMempool fires.
     bool ret = pwallet->chain().broadcastTransaction(
         GetConfig(), tx, pwallet->m_default_max_tx_fee, relay, err_string);
     fInMempool |= ret;
     return ret;
 }
 
 std::set<TxId> CWalletTx::GetConflicts() const {
     std::set<TxId> result;
     if (pwallet != nullptr) {
         const TxId &txid = GetId();
         result = pwallet->GetConflicts(txid);
         result.erase(txid);
     }
 
     return result;
 }
 
 Amount CWalletTx::GetCachableAmount(AmountType type, const isminefilter &filter,
                                     bool recalculate) const {
     auto &amount = m_amounts[type];
     if (recalculate || !amount.m_cached[filter]) {
         amount.Set(filter, type == DEBIT ? pwallet->GetDebit(*tx, filter)
                                          : pwallet->GetCredit(*tx, filter));
         m_is_cache_empty = false;
     }
     return amount.m_value[filter];
 }
 
 Amount CWalletTx::GetDebit(const isminefilter &filter) const {
     if (tx->vin.empty()) {
         return Amount::zero();
     }
 
     Amount debit = Amount::zero();
     if (filter & ISMINE_SPENDABLE) {
         debit += GetCachableAmount(DEBIT, ISMINE_SPENDABLE);
     }
     if (filter & ISMINE_WATCH_ONLY) {
         debit += GetCachableAmount(DEBIT, ISMINE_WATCH_ONLY);
     }
 
     return debit;
 }
 
 Amount CWalletTx::GetCredit(const isminefilter &filter) const {
     // Must wait until coinbase is safely deep enough in the chain before
     // valuing it.
     if (IsImmatureCoinBase()) {
         return Amount::zero();
     }
 
     Amount credit = Amount::zero();
     if (filter & ISMINE_SPENDABLE) {
         // GetBalance can assume transactions in mapWallet won't change.
         credit += GetCachableAmount(CREDIT, ISMINE_SPENDABLE);
     }
 
     if (filter & ISMINE_WATCH_ONLY) {
         credit += GetCachableAmount(CREDIT, ISMINE_WATCH_ONLY);
     }
 
     return credit;
 }
 
 Amount CWalletTx::GetImmatureCredit(bool fUseCache) const {
     if (IsImmatureCoinBase() && IsInMainChain()) {
         return GetCachableAmount(IMMATURE_CREDIT, ISMINE_SPENDABLE, !fUseCache);
     }
 
     return Amount::zero();
 }
 
 Amount CWalletTx::GetAvailableCredit(bool fUseCache,
                                      const isminefilter &filter) const {
     if (pwallet == nullptr) {
         return Amount::zero();
     }
 
     // Avoid caching ismine for NO or ALL cases (could remove this check and
     // simplify in the future).
     bool allow_cache =
         (filter & ISMINE_ALL) && (filter & ISMINE_ALL) != ISMINE_ALL;
 
     // Must wait until coinbase is safely deep enough in the chain before
     // valuing it.
     if (IsImmatureCoinBase()) {
         return Amount::zero();
     }
 
     if (fUseCache && allow_cache &&
         m_amounts[AVAILABLE_CREDIT].m_cached[filter]) {
         return m_amounts[AVAILABLE_CREDIT].m_value[filter];
     }
 
     bool allow_used_addresses =
         (filter & ISMINE_USED) ||
         !pwallet->IsWalletFlagSet(WALLET_FLAG_AVOID_REUSE);
     Amount nCredit = Amount::zero();
     const TxId &txid = GetId();
     for (uint32_t i = 0; i < tx->vout.size(); i++) {
         if (!pwallet->IsSpent(COutPoint(txid, i)) &&
             (allow_used_addresses || !pwallet->IsSpentKey(txid, i))) {
             const CTxOut &txout = tx->vout[i];
             nCredit += pwallet->GetCredit(txout, filter);
             if (!MoneyRange(nCredit)) {
                 throw std::runtime_error(std::string(__func__) +
                                          " : value out of range");
             }
         }
     }
 
     if (allow_cache) {
         m_amounts[AVAILABLE_CREDIT].Set(filter, nCredit);
         m_is_cache_empty = false;
     }
 
     return nCredit;
 }
 
 Amount CWalletTx::GetImmatureWatchOnlyCredit(const bool fUseCache) const {
     if (IsImmatureCoinBase() && IsInMainChain()) {
         return GetCachableAmount(IMMATURE_CREDIT, ISMINE_WATCH_ONLY,
                                  !fUseCache);
     }
 
     return Amount::zero();
 }
 
 Amount CWalletTx::GetChange() const {
     if (fChangeCached) {
         return nChangeCached;
     }
 
     nChangeCached = pwallet->GetChange(*tx);
     fChangeCached = true;
     return nChangeCached;
 }
 
 bool CWalletTx::InMempool() const {
     return fInMempool;
 }
 
 bool CWalletTx::IsTrusted() const {
     std::set<TxId> trusted_parents;
     LOCK(pwallet->cs_wallet);
     return pwallet->IsTrusted(*this, trusted_parents);
 }
 
 bool CWallet::IsTrusted(const CWalletTx &wtx,
                         std::set<TxId> &trusted_parents) const {
     AssertLockHeld(cs_wallet);
     // Quick answer in most cases
     TxValidationState state;
     if (!chain().contextualCheckTransactionForCurrentBlock(*wtx.tx, state)) {
         return false;
     }
 
     int nDepth = wtx.GetDepthInMainChain();
     if (nDepth >= 1) {
         return true;
     }
 
     if (nDepth < 0) {
         return false;
     }
 
     // using wtx's cached debit
     if (!m_spend_zero_conf_change || !wtx.IsFromMe(ISMINE_ALL)) {
         return false;
     }
 
     // Don't trust unconfirmed transactions from us unless they are in the
     // mempool.
     if (!wtx.InMempool()) {
         return false;
     }
 
     // Trusted if all inputs are from us and are in the mempool:
     for (const CTxIn &txin : wtx.tx->vin) {
         // Transactions not sent by us: not trusted
         const CWalletTx *parent = GetWalletTx(txin.prevout.GetTxId());
         if (parent == nullptr) {
             return false;
         }
 
         const CTxOut &parentOut = parent->tx->vout[txin.prevout.GetN()];
         // Check that this specific input being spent is trusted
         if (IsMine(parentOut) != ISMINE_SPENDABLE) {
             return false;
         }
         // If we've already trusted this parent, continue
         if (trusted_parents.count(parent->GetId())) {
             continue;
         }
         // Recurse to check that the parent is also trusted
         if (!IsTrusted(*parent, trusted_parents)) {
             return false;
         }
         trusted_parents.insert(parent->GetId());
     }
 
     return true;
 }
 
 bool CWalletTx::IsEquivalentTo(const CWalletTx &_tx) const {
     CMutableTransaction tx1{*this->tx};
     CMutableTransaction tx2{*_tx.tx};
     for (auto &txin : tx1.vin) {
         txin.scriptSig = CScript();
     }
 
     for (auto &txin : tx2.vin) {
         txin.scriptSig = CScript();
     }
 
     return CTransaction(tx1) == CTransaction(tx2);
 }
 
 // Rebroadcast transactions from the wallet. We do this on a random timer
 // to slightly obfuscate which transactions come from our wallet.
 //
 // Ideally, we'd only resend transactions that we think should have been
 // mined in the most recent block. Any transaction that wasn't in the top
 // blockweight of transactions in the mempool shouldn't have been mined,
 // and so is probably just sitting in the mempool waiting to be confirmed.
 // Rebroadcasting does nothing to speed up confirmation and only damages
 // privacy.
 void CWallet::ResendWalletTransactions() {
     // During reindex, importing and IBD, old wallet transactions become
     // unconfirmed. Don't resend them as that would spam other nodes.
     if (!chain().isReadyToBroadcast()) {
         return;
     }
 
     // Do this infrequently and randomly to avoid giving away that these are our
     // transactions.
     if (GetTime() < nNextResend || !fBroadcastTransactions) {
         return;
     }
 
     bool fFirst = (nNextResend == 0);
     // resend 12-36 hours from now, ~1 day on average.
     nNextResend = GetTime() + (12 * 60 * 60) + GetRand(24 * 60 * 60);
     if (fFirst) {
         return;
     }
 
     int submitted_tx_count = 0;
 
     { // cs_wallet scope
         LOCK(cs_wallet);
 
         // Relay transactions
         for (std::pair<const TxId, CWalletTx> &item : mapWallet) {
             CWalletTx &wtx = item.second;
             // Attempt to rebroadcast all txes more than 5 minutes older than
             // the last block. SubmitMemoryPoolAndRelay() will not rebroadcast
             // any confirmed or conflicting txs.
             if (wtx.nTimeReceived > m_best_block_time - 5 * 60) {
                 continue;
             }
             std::string unused_err_string;
             if (wtx.SubmitMemoryPoolAndRelay(unused_err_string, true)) {
                 ++submitted_tx_count;
             }
         }
     } // cs_wallet
 
     if (submitted_tx_count > 0) {
         WalletLogPrintf("%s: resubmit %u unconfirmed transactions\n", __func__,
                         submitted_tx_count);
     }
 }
 
 /** @} */ // end of mapWallet
 
 void MaybeResendWalletTxs() {
     for (const std::shared_ptr<CWallet> &pwallet : GetWallets()) {
         pwallet->ResendWalletTransactions();
     }
 }
 
 /**
  * @defgroup Actions
  *
  * @{
  */
 CWallet::Balance CWallet::GetBalance(const int min_depth,
                                      bool avoid_reuse) const {
     Balance ret;
     isminefilter reuse_filter = avoid_reuse ? ISMINE_NO : ISMINE_USED;
     LOCK(cs_wallet);
     std::set<TxId> trusted_parents;
     for (const auto &entry : mapWallet) {
         const CWalletTx &wtx = entry.second;
         const bool is_trusted{IsTrusted(wtx, trusted_parents)};
         const int tx_depth{wtx.GetDepthInMainChain()};
         const Amount tx_credit_mine{wtx.GetAvailableCredit(
             /* fUseCache */ true, ISMINE_SPENDABLE | reuse_filter)};
         const Amount tx_credit_watchonly{wtx.GetAvailableCredit(
             /* fUseCache */ true, ISMINE_WATCH_ONLY | reuse_filter)};
         if (is_trusted && tx_depth >= min_depth) {
             ret.m_mine_trusted += tx_credit_mine;
             ret.m_watchonly_trusted += tx_credit_watchonly;
         }
         if (!is_trusted && tx_depth == 0 && wtx.InMempool()) {
             ret.m_mine_untrusted_pending += tx_credit_mine;
             ret.m_watchonly_untrusted_pending += tx_credit_watchonly;
         }
         ret.m_mine_immature += wtx.GetImmatureCredit();
         ret.m_watchonly_immature += wtx.GetImmatureWatchOnlyCredit();
     }
     return ret;
 }
 
 Amount CWallet::GetAvailableBalance(const CCoinControl *coinControl) const {
     LOCK(cs_wallet);
 
     Amount balance = Amount::zero();
     std::vector<COutput> vCoins;
     AvailableCoins(vCoins, true, coinControl);
     for (const COutput &out : vCoins) {
         if (out.fSpendable) {
             balance += out.tx->tx->vout[out.i].nValue;
         }
     }
     return balance;
 }
 
 void CWallet::AvailableCoins(std::vector<COutput> &vCoins, bool fOnlySafe,
                              const CCoinControl *coinControl,
                              const Amount nMinimumAmount,
                              const Amount nMaximumAmount,
                              const Amount nMinimumSumAmount,
                              const uint64_t nMaximumCount) const {
     AssertLockHeld(cs_wallet);
 
     vCoins.clear();
     Amount nTotal = Amount::zero();
     // Either the WALLET_FLAG_AVOID_REUSE flag is not set (in which case we
     // always allow), or we default to avoiding, and only in the case where a
     // coin control object is provided, and has the avoid address reuse flag set
     // to false, do we allow already used addresses
     bool allow_used_addresses =
         !IsWalletFlagSet(WALLET_FLAG_AVOID_REUSE) ||
         (coinControl && !coinControl->m_avoid_address_reuse);
     const int min_depth = {coinControl ? coinControl->m_min_depth
                                        : DEFAULT_MIN_DEPTH};
     const int max_depth = {coinControl ? coinControl->m_max_depth
                                        : DEFAULT_MAX_DEPTH};
 
     std::set<TxId> trusted_parents;
     for (const auto &entry : mapWallet) {
         const TxId &wtxid = entry.first;
         const CWalletTx &wtx = entry.second;
 
         TxValidationState state;
         if (!chain().contextualCheckTransactionForCurrentBlock(*wtx.tx,
                                                                state)) {
             continue;
         }
 
         if (wtx.IsImmatureCoinBase()) {
             continue;
         }
 
         int nDepth = wtx.GetDepthInMainChain();
         if (nDepth < 0) {
             continue;
         }
 
         // We should not consider coins which aren't at least in our mempool.
         // It's possible for these to be conflicted via ancestors which we may
         // never be able to detect.
         if (nDepth == 0 && !wtx.InMempool()) {
             continue;
         }
 
         bool safeTx = IsTrusted(wtx, trusted_parents);
 
         // Bitcoin-ABC: Removed check that prevents consideration of coins from
         // transactions that are replacing other transactions. This check based
         // on wtx.mapValue.count("replaces_txid") which was not being set
         // anywhere.
 
         // Similarly, we should not consider coins from transactions that have
         // been replaced. In the example above, we would want to prevent
         // creation of a transaction A' spending an output of A, because if
         // transaction B were initially confirmed, conflicting with A and A', we
         // wouldn't want to the user to create a transaction D intending to
         // replace A', but potentially resulting in a scenario where A, A', and
         // D could all be accepted (instead of just B and D, or just A and A'
         // like the user would want).
 
         // Bitcoin-ABC: retained this check as 'replaced_by_txid' is still set
         // in the wallet code.
         if (nDepth == 0 && wtx.mapValue.count("replaced_by_txid")) {
             safeTx = false;
         }
 
         if (fOnlySafe && !safeTx) {
             continue;
         }
 
         if (nDepth < min_depth || nDepth > max_depth) {
             continue;
         }
 
         for (uint32_t i = 0; i < wtx.tx->vout.size(); i++) {
             // Only consider selected coins if add_inputs is false
             if (coinControl && !coinControl->m_add_inputs &&
                 !coinControl->IsSelected(COutPoint(entry.first, i))) {
                 continue;
             }
 
             if (wtx.tx->vout[i].nValue < nMinimumAmount ||
                 wtx.tx->vout[i].nValue > nMaximumAmount) {
                 continue;
             }
 
             const COutPoint outpoint(wtxid, i);
 
             if (coinControl && coinControl->HasSelected() &&
                 !coinControl->fAllowOtherInputs &&
                 !coinControl->IsSelected(outpoint)) {
                 continue;
             }
 
             if (IsLockedCoin(outpoint)) {
                 continue;
             }
 
             if (IsSpent(outpoint)) {
                 continue;
             }
 
             isminetype mine = IsMine(wtx.tx->vout[i]);
 
             if (mine == ISMINE_NO) {
                 continue;
             }
 
             if (!allow_used_addresses && IsSpentKey(wtxid, i)) {
                 continue;
             }
 
             std::unique_ptr<SigningProvider> provider =
                 GetSolvingProvider(wtx.tx->vout[i].scriptPubKey);
 
             bool solvable =
                 provider ? IsSolvable(*provider, wtx.tx->vout[i].scriptPubKey)
                          : false;
             bool spendable =
                 ((mine & ISMINE_SPENDABLE) != ISMINE_NO) ||
                 (((mine & ISMINE_WATCH_ONLY) != ISMINE_NO) &&
                  (coinControl && coinControl->fAllowWatchOnly && solvable));
 
             vCoins.push_back(
                 COutput(&wtx, i, nDepth, spendable, solvable, safeTx,
                         (coinControl && coinControl->fAllowWatchOnly)));
 
             // Checks the sum amount of all UTXO's.
             if (nMinimumSumAmount != MAX_MONEY) {
                 nTotal += wtx.tx->vout[i].nValue;
 
                 if (nTotal >= nMinimumSumAmount) {
                     return;
                 }
             }
 
             // Checks the maximum number of UTXO's.
             if (nMaximumCount > 0 && vCoins.size() >= nMaximumCount) {
                 return;
             }
         }
     }
 }
 
 std::map<CTxDestination, std::vector<COutput>> CWallet::ListCoins() const {
     AssertLockHeld(cs_wallet);
 
     std::map<CTxDestination, std::vector<COutput>> result;
     std::vector<COutput> availableCoins;
 
     AvailableCoins(availableCoins);
 
     for (const auto &coin : availableCoins) {
         CTxDestination address;
         if ((coin.fSpendable ||
              (IsWalletFlagSet(WALLET_FLAG_DISABLE_PRIVATE_KEYS) &&
               coin.fSolvable)) &&
             ExtractDestination(
                 FindNonChangeParentOutput(*coin.tx->tx, coin.i).scriptPubKey,
                 address)) {
             result[address].emplace_back(std::move(coin));
         }
     }
 
     std::vector<COutPoint> lockedCoins;
     ListLockedCoins(lockedCoins);
     // Include watch-only for LegacyScriptPubKeyMan wallets without private keys
     const bool include_watch_only =
         GetLegacyScriptPubKeyMan() &&
         IsWalletFlagSet(WALLET_FLAG_DISABLE_PRIVATE_KEYS);
     const isminetype is_mine_filter =
         include_watch_only ? ISMINE_WATCH_ONLY : ISMINE_SPENDABLE;
     for (const auto &output : lockedCoins) {
         auto it = mapWallet.find(output.GetTxId());
         if (it != mapWallet.end()) {
             int depth = it->second.GetDepthInMainChain();
             if (depth >= 0 && output.GetN() < it->second.tx->vout.size() &&
                 IsMine(it->second.tx->vout[output.GetN()]) == is_mine_filter) {
                 CTxDestination address;
                 if (ExtractDestination(
                         FindNonChangeParentOutput(*it->second.tx, output.GetN())
                             .scriptPubKey,
                         address)) {
                     result[address].emplace_back(
                         &it->second, output.GetN(), depth, true /* spendable */,
                         true /* solvable */, false /* safe */);
                 }
             }
         }
     }
 
     return result;
 }
 
 const CTxOut &CWallet::FindNonChangeParentOutput(const CTransaction &tx,
                                                  int output) const {
     AssertLockHeld(cs_wallet);
     const CTransaction *ptx = &tx;
     int n = output;
     while (IsChange(ptx->vout[n]) && ptx->vin.size() > 0) {
         const COutPoint &prevout = ptx->vin[0].prevout;
         auto it = mapWallet.find(prevout.GetTxId());
         if (it == mapWallet.end() ||
             it->second.tx->vout.size() <= prevout.GetN() ||
             !IsMine(it->second.tx->vout[prevout.GetN()])) {
             break;
         }
         ptx = it->second.tx.get();
         n = prevout.GetN();
     }
     return ptx->vout[n];
 }
 
 bool CWallet::SelectCoinsMinConf(
     const Amount nTargetValue, const CoinEligibilityFilter &eligibility_filter,
     std::vector<OutputGroup> groups, std::set<CInputCoin> &setCoinsRet,
     Amount &nValueRet, const CoinSelectionParams &coin_selection_params,
     bool &bnb_used) const {
     setCoinsRet.clear();
     nValueRet = Amount::zero();
 
     std::vector<OutputGroup> utxo_pool;
     if (coin_selection_params.use_bnb) {
         // Get long term estimate
         CCoinControl temp;
         temp.m_confirm_target = 1008;
         CFeeRate long_term_feerate = GetMinimumFeeRate(*this, temp);
 
         // Calculate cost of change
         Amount cost_of_change = chain().relayDustFee().GetFee(
                                     coin_selection_params.change_spend_size) +
                                 coin_selection_params.effective_fee.GetFee(
                                     coin_selection_params.change_output_size);
 
         // Filter by the min conf specs and add to utxo_pool and calculate
         // effective value
         for (OutputGroup &group : groups) {
             if (!group.EligibleForSpending(eligibility_filter)) {
                 continue;
             }
 
             if (coin_selection_params.m_subtract_fee_outputs) {
                 // Set the effective feerate to 0 as we don't want to use the
                 // effective value since the fees will be deducted from the
                 // output
                 group.SetFees(CFeeRate(Amount::zero()) /* effective_feerate */,
                               long_term_feerate);
             } else {
                 group.SetFees(coin_selection_params.effective_fee,
                               long_term_feerate);
             }
 
             OutputGroup pos_group = group.GetPositiveOnlyGroup();
             if (pos_group.effective_value > Amount::zero()) {
                 utxo_pool.push_back(pos_group);
             }
         }
         // Calculate the fees for things that aren't inputs
         Amount not_input_fees = coin_selection_params.effective_fee.GetFee(
             coin_selection_params.tx_noinputs_size);
         bnb_used = true;
         return SelectCoinsBnB(utxo_pool, nTargetValue, cost_of_change,
                               setCoinsRet, nValueRet, not_input_fees);
     } else {
         // Filter by the min conf specs and add to utxo_pool
         for (const OutputGroup &group : groups) {
             if (!group.EligibleForSpending(eligibility_filter)) {
                 continue;
             }
             utxo_pool.push_back(group);
         }
         bnb_used = false;
         return KnapsackSolver(nTargetValue, utxo_pool, setCoinsRet, nValueRet);
     }
 }
 
 bool CWallet::SelectCoins(const std::vector<COutput> &vAvailableCoins,
                           const Amount nTargetValue,
                           std::set<CInputCoin> &setCoinsRet, Amount &nValueRet,
                           const CCoinControl &coin_control,
                           CoinSelectionParams &coin_selection_params,
                           bool &bnb_used) const {
     std::vector<COutput> vCoins(vAvailableCoins);
     Amount value_to_select = nTargetValue;
 
     // Default to bnb was not used. If we use it, we set it later
     bnb_used = false;
 
     // coin control -> return all selected outputs (we want all selected to go
     // into the transaction for sure)
     if (coin_control.HasSelected() && !coin_control.fAllowOtherInputs) {
         for (const COutput &out : vCoins) {
             if (!out.fSpendable) {
                 continue;
             }
 
             nValueRet += out.tx->tx->vout[out.i].nValue;
             setCoinsRet.insert(out.GetInputCoin());
         }
 
         return (nValueRet >= nTargetValue);
     }
 
     // Calculate value from preset inputs and store them.
     std::set<CInputCoin> setPresetCoins;
     Amount nValueFromPresetInputs = Amount::zero();
 
     std::vector<COutPoint> vPresetInputs;
     coin_control.ListSelected(vPresetInputs);
 
     for (const COutPoint &outpoint : vPresetInputs) {
         std::map<TxId, CWalletTx>::const_iterator it =
             mapWallet.find(outpoint.GetTxId());
         if (it != mapWallet.end()) {
             const CWalletTx &wtx = it->second;
             // Clearly invalid input, fail
             if (wtx.tx->vout.size() <= outpoint.GetN()) {
                 return false;
             }
             // Just to calculate the marginal byte size
             CInputCoin coin(wtx.tx, outpoint.GetN(),
                             wtx.GetSpendSize(outpoint.GetN(), false));
             nValueFromPresetInputs += coin.txout.nValue;
             if (coin.m_input_bytes <= 0) {
                 // Not solvable, can't estimate size for fee
                 return false;
             }
             coin.effective_value =
                 coin.txout.nValue -
                 coin_selection_params.effective_fee.GetFee(coin.m_input_bytes);
             if (coin_selection_params.use_bnb) {
                 value_to_select -= coin.effective_value;
             } else {
                 value_to_select -= coin.txout.nValue;
             }
             setPresetCoins.insert(coin);
         } else {
             return false; // TODO: Allow non-wallet inputs
         }
     }
 
     // Remove preset inputs from vCoins
     for (std::vector<COutput>::iterator it = vCoins.begin();
          it != vCoins.end() && coin_control.HasSelected();) {
         if (setPresetCoins.count(it->GetInputCoin())) {
             it = vCoins.erase(it);
         } else {
             ++it;
         }
     }
 
     size_t max_ancestors{0};
     size_t max_descendants{0};
     chain().getPackageLimits(max_ancestors, max_descendants);
     bool fRejectLongChains = gArgs.GetBoolArg(
         "-walletrejectlongchains", DEFAULT_WALLET_REJECT_LONG_CHAINS);
 
     // form groups from remaining coins; note that preset coins will not
     // automatically have their associated (same address) coins included
     if (coin_control.m_avoid_partial_spends &&
         vCoins.size() > OUTPUT_GROUP_MAX_ENTRIES) {
         // Cases where we have 11+ outputs all pointing to the same destination
         // may result in privacy leaks as they will potentially be
         // deterministically sorted. We solve that by explicitly shuffling the
         // outputs before processing
         Shuffle(vCoins.begin(), vCoins.end(), FastRandomContext());
     }
 
     std::vector<OutputGroup> groups = GroupOutputs(
         vCoins, !coin_control.m_avoid_partial_spends, max_ancestors);
 
     bool res =
         value_to_select <= Amount::zero() ||
         SelectCoinsMinConf(value_to_select, CoinEligibilityFilter(1, 6, 0),
                            groups, setCoinsRet, nValueRet,
                            coin_selection_params, bnb_used) ||
         SelectCoinsMinConf(value_to_select, CoinEligibilityFilter(1, 1, 0),
                            groups, setCoinsRet, nValueRet,
                            coin_selection_params, bnb_used) ||
         (m_spend_zero_conf_change &&
          SelectCoinsMinConf(value_to_select, CoinEligibilityFilter(0, 1, 2),
                             groups, setCoinsRet, nValueRet,
                             coin_selection_params, bnb_used)) ||
         (m_spend_zero_conf_change &&
          SelectCoinsMinConf(
              value_to_select,
              CoinEligibilityFilter(0, 1, std::min((size_t)4, max_ancestors / 3),
                                    std::min((size_t)4, max_descendants / 3)),
              groups, setCoinsRet, nValueRet, coin_selection_params,
              bnb_used)) ||
         (m_spend_zero_conf_change &&
          SelectCoinsMinConf(value_to_select,
                             CoinEligibilityFilter(0, 1, max_ancestors / 2,
                                                   max_descendants / 2),
                             groups, setCoinsRet, nValueRet,
                             coin_selection_params, bnb_used)) ||
         (m_spend_zero_conf_change &&
          SelectCoinsMinConf(value_to_select,
                             CoinEligibilityFilter(0, 1, max_ancestors - 1,
                                                   max_descendants - 1),
                             groups, setCoinsRet, nValueRet,
                             coin_selection_params, bnb_used)) ||
         (m_spend_zero_conf_change && !fRejectLongChains &&
          SelectCoinsMinConf(
              value_to_select,
              CoinEligibilityFilter(0, 1, std::numeric_limits<uint64_t>::max()),
              groups, setCoinsRet, nValueRet, coin_selection_params, bnb_used));
 
     // Because SelectCoinsMinConf clears the setCoinsRet, we now add the
     // possible inputs to the coinset.
     util::insert(setCoinsRet, setPresetCoins);
 
     // Add preset inputs to the total value selected.
     nValueRet += nValueFromPresetInputs;
 
     return res;
 }
 
 bool CWallet::SignTransaction(CMutableTransaction &tx) const {
     AssertLockHeld(cs_wallet);
 
     // Build coins map
     std::map<COutPoint, Coin> coins;
     for (auto &input : tx.vin) {
         auto mi = mapWallet.find(input.prevout.GetTxId());
         if (mi == mapWallet.end() ||
             input.prevout.GetN() >= mi->second.tx->vout.size()) {
             return false;
         }
         const CWalletTx &wtx = mi->second;
         coins[input.prevout] =
             Coin(wtx.tx->vout[input.prevout.GetN()], wtx.m_confirm.block_height,
                  wtx.IsCoinBase());
     }
     std::map<int, std::string> input_errors;
     return SignTransaction(tx, coins, SigHashType().withForkId(), input_errors);
 }
 
 bool CWallet::SignTransaction(CMutableTransaction &tx,
                               const std::map<COutPoint, Coin> &coins,
                               SigHashType sighash,
                               std::map<int, std::string> &input_errors) const {
     // Try to sign with all ScriptPubKeyMans
     for (ScriptPubKeyMan *spk_man : GetAllScriptPubKeyMans()) {
         // spk_man->SignTransaction will return true if the transaction is
         // complete, so we can exit early and return true if that happens
         if (spk_man->SignTransaction(tx, coins, sighash, input_errors)) {
             return true;
         }
     }
 
     // At this point, one input was not fully signed otherwise we would have
     // exited already
 
     // When there are no available providers for the remaining inputs, use the
     // legacy provider so we can get proper error messages.
     auto legacy_spk_man = GetLegacyScriptPubKeyMan();
     if (legacy_spk_man &&
         legacy_spk_man->SignTransaction(tx, coins, sighash, input_errors)) {
         return true;
     }
 
     return false;
 }
 
 TransactionError CWallet::FillPSBT(PartiallySignedTransaction &psbtx,
                                    bool &complete, SigHashType sighash_type,
                                    bool sign, bool bip32derivs) const {
     LOCK(cs_wallet);
     // Get all of the previous transactions
     for (size_t i = 0; i < psbtx.tx->vin.size(); ++i) {
         const CTxIn &txin = psbtx.tx->vin[i];
         PSBTInput &input = psbtx.inputs.at(i);
 
         if (PSBTInputSigned(input)) {
             continue;
         }
 
         // If we have no utxo, grab it from the wallet.
         if (input.utxo.IsNull()) {
             const TxId &txid = txin.prevout.GetTxId();
             const auto it = mapWallet.find(txid);
             if (it != mapWallet.end()) {
                 const CWalletTx &wtx = it->second;
                 CTxOut utxo = wtx.tx->vout[txin.prevout.GetN()];
                 // Update UTXOs from the wallet.
                 input.utxo = utxo;
             }
         }
     }
 
     // Fill in information from ScriptPubKeyMans
     for (ScriptPubKeyMan *spk_man : GetAllScriptPubKeyMans()) {
         TransactionError res =
             spk_man->FillPSBT(psbtx, sighash_type, sign, bip32derivs);
         if (res != TransactionError::OK) {
             return res;
         }
     }
 
     // Complete if every input is now signed
     complete = true;
     for (const auto &input : psbtx.inputs) {
         complete &= PSBTInputSigned(input);
     }
 
     return TransactionError::OK;
 }
 
 SigningResult CWallet::SignMessage(const std::string &message,
                                    const PKHash &pkhash,
                                    std::string &str_sig) const {
     SignatureData sigdata;
     CScript script_pub_key = GetScriptForDestination(pkhash);
     for (const auto &spk_man_pair : m_spk_managers) {
         if (spk_man_pair.second->CanProvide(script_pub_key, sigdata)) {
             return spk_man_pair.second->SignMessage(message, pkhash, str_sig);
         }
     }
     return SigningResult::PRIVATE_KEY_NOT_AVAILABLE;
 }
 
 bool CWallet::FundTransaction(CMutableTransaction &tx, Amount &nFeeRet,
                               int &nChangePosInOut, bilingual_str &error,
                               bool lockUnspents,
                               const std::set<int> &setSubtractFeeFromOutputs,
                               CCoinControl coinControl) {
     std::vector<CRecipient> vecSend;
 
     // Turn the txout set into a CRecipient vector.
     for (size_t idx = 0; idx < tx.vout.size(); idx++) {
         const CTxOut &txOut = tx.vout[idx];
         CRecipient recipient = {txOut.scriptPubKey, txOut.nValue,
                                 setSubtractFeeFromOutputs.count(idx) == 1};
         vecSend.push_back(recipient);
     }
 
     coinControl.fAllowOtherInputs = true;
 
     for (const CTxIn &txin : tx.vin) {
         coinControl.Select(txin.prevout);
     }
 
     // Acquire the locks to prevent races to the new locked unspents between the
     // CreateTransaction call and LockCoin calls (when lockUnspents is true).
     LOCK(cs_wallet);
 
     CTransactionRef tx_new;
     if (!CreateTransaction(vecSend, tx_new, nFeeRet, nChangePosInOut, error,
                            coinControl, false)) {
         return false;
     }
 
     if (nChangePosInOut != -1) {
         tx.vout.insert(tx.vout.begin() + nChangePosInOut,
                        tx_new->vout[nChangePosInOut]);
     }
 
     // Copy output sizes from new transaction; they may have had the fee
     // subtracted from them.
     for (size_t idx = 0; idx < tx.vout.size(); idx++) {
         tx.vout[idx].nValue = tx_new->vout[idx].nValue;
     }
 
     // Add new txins (keeping original txin scriptSig/order)
     for (const CTxIn &txin : tx_new->vin) {
         if (!coinControl.IsSelected(txin.prevout)) {
             tx.vin.push_back(txin);
         }
         if (lockUnspents) {
             LockCoin(txin.prevout);
         }
     }
 
     return true;
 }
 
 static bool IsCurrentForAntiFeeSniping(interfaces::Chain &chain,
                                        const BlockHash &block_hash) {
     if (chain.isInitialBlockDownload()) {
         return false;
     }
 
     // in seconds
     constexpr int64_t MAX_ANTI_FEE_SNIPING_TIP_AGE = 8 * 60 * 60;
     int64_t block_time;
     CHECK_NONFATAL(chain.findBlock(block_hash, FoundBlock().time(block_time)));
     if (block_time < (GetTime() - MAX_ANTI_FEE_SNIPING_TIP_AGE)) {
         return false;
     }
     return true;
 }
 
 /**
  * Return a height-based locktime for new transactions (uses the height of the
  * current chain tip unless we are not synced with the current chain
  */
 static uint32_t GetLocktimeForNewTransaction(interfaces::Chain &chain,
                                              const BlockHash &block_hash,
                                              int block_height) {
     uint32_t locktime;
     // Discourage fee sniping.
     //
     // For a large miner the value of the transactions in the best block and
     // the mempool can exceed the cost of deliberately attempting to mine two
     // blocks to orphan the current best block. By setting nLockTime such that
     // only the next block can include the transaction, we discourage this
     // practice as the height restricted and limited blocksize gives miners
     // considering fee sniping fewer options for pulling off this attack.
     //
     // A simple way to think about this is from the wallet's point of view we
     // always want the blockchain to move forward. By setting nLockTime this
     // way we're basically making the statement that we only want this
     // transaction to appear in the next block; we don't want to potentially
     // encourage reorgs by allowing transactions to appear at lower heights
     // than the next block in forks of the best chain.
     //
     // Of course, the subsidy is high enough, and transaction volume low
     // enough, that fee sniping isn't a problem yet, but by implementing a fix
     // now we ensure code won't be written that makes assumptions about
     // nLockTime that preclude a fix later.
     if (IsCurrentForAntiFeeSniping(chain, block_hash)) {
         locktime = block_height;
 
         // Secondly occasionally randomly pick a nLockTime even further back, so
         // that transactions that are delayed after signing for whatever reason,
         // e.g. high-latency mix networks and some CoinJoin implementations,
         // have better privacy.
         if (GetRandInt(10) == 0) {
             locktime = std::max(0, int(locktime) - GetRandInt(100));
         }
     } else {
         // If our chain is lagging behind, we can't discourage fee sniping nor
         // help the privacy of high-latency transactions. To avoid leaking a
         // potentially unique "nLockTime fingerprint", set nLockTime to a
         // constant.
         locktime = 0;
     }
     assert(locktime < LOCKTIME_THRESHOLD);
     return locktime;
 }
 
 OutputType
 CWallet::TransactionChangeType(const std::optional<OutputType> &change_type,
                                const std::vector<CRecipient> &vecSend) {
     // If -changetype is specified, always use that change type.
     if (change_type) {
         return *change_type;
     }
 
     // if m_default_address_type is legacy, use legacy address as change.
     if (m_default_address_type == OutputType::LEGACY) {
         return OutputType::LEGACY;
     }
 
     // else use m_default_address_type for change
     return m_default_address_type;
 }
 
 bool CWallet::CreateTransactionInternal(const std::vector<CRecipient> &vecSend,
                                         CTransactionRef &tx, Amount &nFeeRet,
                                         int &nChangePosInOut,
                                         bilingual_str &error,
                                         const CCoinControl &coin_control,
                                         bool sign) {
     Amount nValue = Amount::zero();
     const OutputType change_type = TransactionChangeType(
         coin_control.m_change_type ? *coin_control.m_change_type
                                    : m_default_change_type,
         vecSend);
     ReserveDestination reservedest(this, change_type);
     int nChangePosRequest = nChangePosInOut;
     unsigned int nSubtractFeeFromAmount = 0;
     for (const auto &recipient : vecSend) {
         if (nValue < Amount::zero() || recipient.nAmount < Amount::zero()) {
             error = _("Transaction amounts must not be negative");
             return false;
         }
 
         nValue += recipient.nAmount;
 
         if (recipient.fSubtractFeeFromAmount) {
             nSubtractFeeFromAmount++;
         }
     }
 
     if (vecSend.empty()) {
         error = _("Transaction must have at least one recipient");
         return false;
     }
 
     CMutableTransaction txNew;
 
     {
         std::set<CInputCoin> setCoins;
         LOCK(cs_wallet);
         txNew.nLockTime = GetLocktimeForNewTransaction(
             chain(), GetLastBlockHash(), GetLastBlockHeight());
         std::vector<COutput> vAvailableCoins;
         AvailableCoins(vAvailableCoins, true, &coin_control);
         // Parameters for coin selection, init with dummy
         CoinSelectionParams coin_selection_params;
 
         // Create change script that will be used if we need change
         // TODO: pass in scriptChange instead of reservedest so
         // change transaction isn't always pay-to-bitcoin-address
         CScript scriptChange;
 
         // coin control: send change to custom address
         if (!boost::get<CNoDestination>(&coin_control.destChange)) {
             scriptChange = GetScriptForDestination(coin_control.destChange);
 
             // no coin control: send change to newly generated address
         } else {
             // Note: We use a new key here to keep it from being obvious
             // which side is the change.
             //  The drawback is that by not reusing a previous key, the
             //  change may be lost if a backup is restored, if the backup
             //  doesn't have the new private key for the change. If we
             //  reused the old key, it would be possible to add code to look
             //  for and rediscover unknown transactions that were written
             //  with keys of ours to recover post-backup change.
 
             // Reserve a new key pair from key pool. If it fails, provide a
             // dummy destination in case we don't need change.
             CTxDestination dest;
             if (!reservedest.GetReservedDestination(dest, true)) {
                 error = _("Transaction needs a change address, but we can't "
                           "generate it. Please call keypoolrefill first.");
             }
 
             scriptChange = GetScriptForDestination(dest);
             // A valid destination implies a change script (and
             // vice-versa). An empty change script will abort later, if the
             // change keypool ran out, but change is required.
             CHECK_NONFATAL(IsValidDestination(dest) != scriptChange.empty());
         }
         CTxOut change_prototype_txout(Amount::zero(), scriptChange);
         coin_selection_params.change_output_size =
             GetSerializeSize(change_prototype_txout);
 
         // Get the fee rate to use effective values in coin selection
         CFeeRate nFeeRateNeeded = GetMinimumFeeRate(*this, coin_control);
         // Do not, ever, assume that it's fine to change the fee rate if the
         // user has explicitly provided one
         if (coin_control.m_feerate &&
             nFeeRateNeeded > *coin_control.m_feerate) {
             error = strprintf(_("Fee rate (%s) is lower than the minimum fee "
                                 "rate setting (%s)"),
                               coin_control.m_feerate->ToString(),
                               nFeeRateNeeded.ToString());
             return false;
         }
 
         nFeeRet = Amount::zero();
         bool pick_new_inputs = true;
         Amount nValueIn = Amount::zero();
 
         // BnB selector is the only selector used when this is true.
         // That should only happen on the first pass through the loop.
         coin_selection_params.use_bnb = true;
         // If we are doing subtract fee from recipient, don't use effective
         // values
         coin_selection_params.m_subtract_fee_outputs =
             nSubtractFeeFromAmount != 0;
         // Start with no fee and loop until there is enough fee
         while (true) {
             nChangePosInOut = nChangePosRequest;
             txNew.vin.clear();
             txNew.vout.clear();
             bool fFirst = true;
 
             Amount nValueToSelect = nValue;
             if (nSubtractFeeFromAmount == 0) {
                 nValueToSelect += nFeeRet;
             }
 
             // vouts to the payees
             if (!coin_selection_params.m_subtract_fee_outputs) {
                 // Static size overhead + outputs vsize. 4 nVersion, 4
                 // nLocktime, 1 input count, 1 output count
                 coin_selection_params.tx_noinputs_size = 10;
             }
             // vouts to the payees
             for (const auto &recipient : vecSend) {
                 CTxOut txout(recipient.nAmount, recipient.scriptPubKey);
 
                 if (recipient.fSubtractFeeFromAmount) {
                     assert(nSubtractFeeFromAmount != 0);
                     // Subtract fee equally from each selected recipient.
                     txout.nValue -= nFeeRet / int(nSubtractFeeFromAmount);
 
                     // First receiver pays the remainder not divisible by output
                     // count.
                     if (fFirst) {
                         fFirst = false;
                         txout.nValue -= nFeeRet % int(nSubtractFeeFromAmount);
                     }
                 }
 
                 // Include the fee cost for outputs. Note this is only used for
                 // BnB right now
                 if (!coin_selection_params.m_subtract_fee_outputs) {
                     coin_selection_params.tx_noinputs_size +=
                         ::GetSerializeSize(txout, PROTOCOL_VERSION);
                 }
 
                 if (IsDust(txout, chain().relayDustFee())) {
                     if (recipient.fSubtractFeeFromAmount &&
                         nFeeRet > Amount::zero()) {
                         if (txout.nValue < Amount::zero()) {
                             error = _("The transaction amount is too small to "
                                       "pay the fee");
                         } else {
                             error = _("The transaction amount is too small to "
                                       "send after the fee has been deducted");
                         }
                     } else {
                         error = _("Transaction amount too small");
                     }
 
                     return false;
                 }
 
                 txNew.vout.push_back(txout);
             }
 
             // Choose coins to use
             bool bnb_used = false;
             if (pick_new_inputs) {
                 nValueIn = Amount::zero();
                 setCoins.clear();
                 int change_spend_size = CalculateMaximumSignedInputSize(
                     change_prototype_txout, this);
                 // If the wallet doesn't know how to sign change output, assume
                 // p2pkh as lower-bound to allow BnB to do it's thing
                 if (change_spend_size == -1) {
                     coin_selection_params.change_spend_size =
                         DUMMY_P2PKH_INPUT_SIZE;
                 } else {
                     coin_selection_params.change_spend_size =
                         size_t(change_spend_size);
                 }
                 coin_selection_params.effective_fee = nFeeRateNeeded;
                 if (!SelectCoins(vAvailableCoins, nValueToSelect, setCoins,
                                  nValueIn, coin_control, coin_selection_params,
                                  bnb_used)) {
                     // If BnB was used, it was the first pass. No longer the
                     // first pass and continue loop with knapsack.
                     if (bnb_used) {
                         coin_selection_params.use_bnb = false;
                         continue;
                     } else {
                         error = _("Insufficient funds");
                         return false;
                     }
                 }
             } else {
                 bnb_used = false;
             }
 
             const Amount nChange = nValueIn - nValueToSelect;
             if (nChange > Amount::zero()) {
                 // Fill a vout to ourself.
                 CTxOut newTxOut(nChange, scriptChange);
 
                 // Never create dust outputs; if we would, just add the dust to
                 // the fee.
                 // The nChange when BnB is used is always going to go to fees.
                 if (IsDust(newTxOut, chain().relayDustFee()) || bnb_used) {
                     nChangePosInOut = -1;
                     nFeeRet += nChange;
                 } else {
                     if (nChangePosInOut == -1) {
                         // Insert change txn at random position:
                         nChangePosInOut = GetRandInt(txNew.vout.size() + 1);
                     } else if ((unsigned int)nChangePosInOut >
                                txNew.vout.size()) {
                         error = _("Change index out of range");
                         return false;
                     }
 
                     std::vector<CTxOut>::iterator position =
                         txNew.vout.begin() + nChangePosInOut;
                     txNew.vout.insert(position, newTxOut);
                 }
             } else {
                 nChangePosInOut = -1;
             }
 
             // Dummy fill vin for maximum size estimation
             //
             for (const auto &coin : setCoins) {
                 txNew.vin.push_back(CTxIn(coin.outpoint, CScript()));
             }
 
             CTransaction txNewConst(txNew);
             int nBytes = CalculateMaximumSignedTxSize(
                 txNewConst, this, coin_control.fAllowWatchOnly);
             if (nBytes < 0) {
                 error = _("Signing transaction failed");
                 return false;
             }
 
             Amount nFeeNeeded = GetMinimumFee(*this, nBytes, coin_control);
 
             if (nFeeRet >= nFeeNeeded) {
                 // Reduce fee to only the needed amount if possible. This
                 // prevents potential overpayment in fees if the coins selected
                 // to meet nFeeNeeded result in a transaction that requires less
                 // fee than the prior iteration.
 
                 // If we have no change and a big enough excess fee, then try to
                 // construct transaction again only without picking new inputs.
                 // We now know we only need the smaller fee (because of reduced
                 // tx size) and so we should add a change output. Only try this
                 // once.
                 if (nChangePosInOut == -1 && nSubtractFeeFromAmount == 0 &&
                     pick_new_inputs) {
                     // Add 2 as a buffer in case increasing # of outputs changes
                     // compact size
                     unsigned int tx_size_with_change =
                         nBytes + coin_selection_params.change_output_size + 2;
                     Amount fee_needed_with_change =
                         GetMinimumFee(*this, tx_size_with_change, coin_control);
                     Amount minimum_value_for_change = GetDustThreshold(
                         change_prototype_txout, chain().relayDustFee());
                     if (nFeeRet >=
                         fee_needed_with_change + minimum_value_for_change) {
                         pick_new_inputs = false;
                         nFeeRet = fee_needed_with_change;
                         continue;
                     }
                 }
 
                 // If we have change output already, just increase it
                 if (nFeeRet > nFeeNeeded && nChangePosInOut != -1 &&
                     nSubtractFeeFromAmount == 0) {
                     Amount extraFeePaid = nFeeRet - nFeeNeeded;
                     std::vector<CTxOut>::iterator change_position =
                         txNew.vout.begin() + nChangePosInOut;
                     change_position->nValue += extraFeePaid;
                     nFeeRet -= extraFeePaid;
                 }
 
                 // Done, enough fee included.
                 break;
             } else if (!pick_new_inputs) {
                 // This shouldn't happen, we should have had enough excess fee
                 // to pay for the new output and still meet nFeeNeeded.
                 // Or we should have just subtracted fee from recipients and
                 // nFeeNeeded should not have changed.
                 error = _("Transaction fee and change calculation failed");
                 return false;
             }
 
             // Try to reduce change to include necessary fee.
             if (nChangePosInOut != -1 && nSubtractFeeFromAmount == 0) {
                 Amount additionalFeeNeeded = nFeeNeeded - nFeeRet;
                 std::vector<CTxOut>::iterator change_position =
                     txNew.vout.begin() + nChangePosInOut;
                 // Only reduce change if remaining amount is still a large
                 // enough output.
                 if (change_position->nValue >=
                     MIN_FINAL_CHANGE + additionalFeeNeeded) {
                     change_position->nValue -= additionalFeeNeeded;
                     nFeeRet += additionalFeeNeeded;
                     // Done, able to increase fee from change.
                     break;
                 }
             }
 
             // If subtracting fee from recipients, we now know what fee we
             // need to subtract, we have no reason to reselect inputs.
             if (nSubtractFeeFromAmount > 0) {
                 pick_new_inputs = false;
             }
 
             // Include more fee and try again.
             nFeeRet = nFeeNeeded;
             coin_selection_params.use_bnb = false;
             continue;
         }
 
         // Give up if change keypool ran out and change is required
         if (scriptChange.empty() && nChangePosInOut != -1) {
             return false;
         }
 
         // Shuffle selected coins and fill in final vin
         txNew.vin.clear();
         std::vector<CInputCoin> selected_coins(setCoins.begin(),
                                                setCoins.end());
         Shuffle(selected_coins.begin(), selected_coins.end(),
                 FastRandomContext());
 
         // Note how the sequence number is set to non-maxint so that
         // the nLockTime set above actually works.
         for (const auto &coin : selected_coins) {
             txNew.vin.push_back(
                 CTxIn(coin.outpoint, CScript(),
                       std::numeric_limits<uint32_t>::max() - 1));
         }
 
         if (sign && !SignTransaction(txNew)) {
             error = _("Signing transaction failed");
             return false;
         }
 
         // Return the constructed transaction data.
         tx = MakeTransactionRef(std::move(txNew));
 
         // Limit size.
         if (tx->GetTotalSize() > MAX_STANDARD_TX_SIZE) {
             error = _("Transaction too large");
             return false;
         }
     }
 
     if (nFeeRet > m_default_max_tx_fee) {
         error = TransactionErrorString(TransactionError::MAX_FEE_EXCEEDED);
         return false;
     }
 
     if (gArgs.GetBoolArg("-walletrejectlongchains",
                          DEFAULT_WALLET_REJECT_LONG_CHAINS)) {
         // Lastly, ensure this tx will pass the mempool's chain limits
         if (!chain().checkChainLimits(tx)) {
             error = _("Transaction has too long of a mempool chain");
             return false;
         }
     }
 
     // Before we return success, we assume any change key will be used to
     // prevent accidental re-use.
     reservedest.KeepDestination();
 
     return true;
 }
 
 bool CWallet::CreateTransaction(const std::vector<CRecipient> &vecSend,
                                 CTransactionRef &tx, Amount &nFeeRet,
                                 int &nChangePosInOut, bilingual_str &error,
                                 const CCoinControl &coin_control, bool sign) {
     int nChangePosIn = nChangePosInOut;
     CTransactionRef tx2 = tx;
     bool res = CreateTransactionInternal(vecSend, tx, nFeeRet, nChangePosInOut,
                                          error, coin_control, sign);
     // try with avoidpartialspends unless it's enabled already
     if (res &&
         nFeeRet >
             Amount::zero() /* 0 means non-functional fee rate estimation */
         && m_max_aps_fee > (-1 * SATOSHI) &&
         !coin_control.m_avoid_partial_spends) {
         CCoinControl tmp_cc = coin_control;
         tmp_cc.m_avoid_partial_spends = true;
         Amount nFeeRet2;
         int nChangePosInOut2 = nChangePosIn;
         // fired and forgotten; if an error occurs, we discard the results
         bilingual_str error2;
         if (CreateTransactionInternal(vecSend, tx2, nFeeRet2, nChangePosInOut2,
                                       error2, tmp_cc, sign)) {
             // if fee of this alternative one is within the range of the max
             // fee, we use this one
             const bool use_aps = nFeeRet2 <= nFeeRet + m_max_aps_fee;
             WalletLogPrintf(
                 "Fee non-grouped = %lld, grouped = %lld, using %s\n", nFeeRet,
                 nFeeRet2, use_aps ? "grouped" : "non-grouped");
             if (use_aps) {
                 tx = tx2;
                 nFeeRet = nFeeRet2;
                 nChangePosInOut = nChangePosInOut2;
             }
         }
     }
     return res;
 }
 
 void CWallet::CommitTransaction(
     CTransactionRef tx, mapValue_t mapValue,
     std::vector<std::pair<std::string, std::string>> orderForm) {
     LOCK(cs_wallet);
 
     WalletLogPrintfToBeContinued("CommitTransaction:\n%s", tx->ToString());
 
     // Add tx to wallet, because if it has change it's also ours, otherwise just
     // for transaction history.
     AddToWallet(tx, {}, [&](CWalletTx &wtx, bool new_tx) {
         CHECK_NONFATAL(wtx.mapValue.empty());
         CHECK_NONFATAL(wtx.vOrderForm.empty());
         wtx.mapValue = std::move(mapValue);
         wtx.vOrderForm = std::move(orderForm);
         wtx.fTimeReceivedIsTxTime = true;
         wtx.fFromMe = true;
         return true;
     });
 
     // Notify that old coins are spent.
     for (const CTxIn &txin : tx->vin) {
         CWalletTx &coin = mapWallet.at(txin.prevout.GetTxId());
         coin.MarkDirty();
         NotifyTransactionChanged(this, coin.GetId(), CT_UPDATED);
     }
 
     // Get the inserted-CWalletTx from mapWallet so that the
     // fInMempool flag is cached properly
     CWalletTx &wtx = mapWallet.at(tx->GetId());
 
     if (!fBroadcastTransactions) {
         // Don't submit tx to the mempool
         return;
     }
 
     std::string err_string;
     if (!wtx.SubmitMemoryPoolAndRelay(err_string, true)) {
         WalletLogPrintf("CommitTransaction(): Transaction cannot be broadcast "
                         "immediately, %s\n",
                         err_string);
         // TODO: if we expect the failure to be long term or permanent, instead
         // delete wtx from the wallet and return failure.
     }
 }
 
 DBErrors CWallet::LoadWallet(bool &fFirstRunRet) {
     LOCK(cs_wallet);
 
     fFirstRunRet = false;
     DBErrors nLoadWalletRet = WalletBatch(*database, "cr+").LoadWallet(this);
     if (nLoadWalletRet == DBErrors::NEED_REWRITE) {
         if (database->Rewrite("\x04pool")) {
             for (const auto &spk_man_pair : m_spk_managers) {
                 spk_man_pair.second->RewriteDB();
             }
         }
     }
 
     // This wallet is in its first run if there are no ScriptPubKeyMans and it
     // isn't blank or no privkeys
     fFirstRunRet = m_spk_managers.empty() &&
                    !IsWalletFlagSet(WALLET_FLAG_DISABLE_PRIVATE_KEYS) &&
                    !IsWalletFlagSet(WALLET_FLAG_BLANK_WALLET);
     if (fFirstRunRet) {
         assert(m_external_spk_managers.empty());
         assert(m_internal_spk_managers.empty());
     }
 
     if (nLoadWalletRet != DBErrors::LOAD_OK) {
         return nLoadWalletRet;
     }
 
     return DBErrors::LOAD_OK;
 }
 
 DBErrors CWallet::ZapSelectTx(std::vector<TxId> &txIdsIn,
                               std::vector<TxId> &txIdsOut) {
     AssertLockHeld(cs_wallet);
     DBErrors nZapSelectTxRet =
         WalletBatch(*database, "cr+").ZapSelectTx(txIdsIn, txIdsOut);
     for (const TxId &txid : txIdsOut) {
         const auto &it = mapWallet.find(txid);
         wtxOrdered.erase(it->second.m_it_wtxOrdered);
         for (const auto &txin : it->second.tx->vin) {
             mapTxSpends.erase(txin.prevout);
         }
         mapWallet.erase(it);
         NotifyTransactionChanged(this, txid, CT_DELETED);
     }
 
     if (nZapSelectTxRet == DBErrors::NEED_REWRITE) {
         if (database->Rewrite("\x04pool")) {
             for (const auto &spk_man_pair : m_spk_managers) {
                 spk_man_pair.second->RewriteDB();
             }
         }
     }
 
     if (nZapSelectTxRet != DBErrors::LOAD_OK) {
         return nZapSelectTxRet;
     }
 
     MarkDirty();
 
     return DBErrors::LOAD_OK;
 }
 
 bool CWallet::SetAddressBookWithDB(WalletBatch &batch,
                                    const CTxDestination &address,
                                    const std::string &strName,
                                    const std::string &strPurpose) {
     bool fUpdated = false;
     bool is_mine;
     {
         LOCK(cs_wallet);
         std::map<CTxDestination, CAddressBookData>::iterator mi =
             m_address_book.find(address);
         fUpdated = (mi != m_address_book.end() && !mi->second.IsChange());
         m_address_book[address].SetLabel(strName);
         // Update purpose only if requested.
         if (!strPurpose.empty()) {
             m_address_book[address].purpose = strPurpose;
         }
         is_mine = IsMine(address) != ISMINE_NO;
     }
 
     NotifyAddressBookChanged(this, address, strName, is_mine, strPurpose,
                              (fUpdated ? CT_UPDATED : CT_NEW));
     if (!strPurpose.empty() && !batch.WritePurpose(address, strPurpose)) {
         return false;
     }
     return batch.WriteName(address, strName);
 }
 
 bool CWallet::SetAddressBook(const CTxDestination &address,
                              const std::string &strName,
                              const std::string &strPurpose) {
     WalletBatch batch(*database);
     return SetAddressBookWithDB(batch, address, strName, strPurpose);
 }
 
 bool CWallet::DelAddressBook(const CTxDestination &address) {
     bool is_mine;
     WalletBatch batch(*database);
     {
         LOCK(cs_wallet);
         // If we want to delete receiving addresses, we need to take care that
         // DestData "used" (and possibly newer DestData) gets preserved (and the
         // "deleted" address transformed into a change entry instead of actually
         // being deleted)
         // NOTE: This isn't a problem for sending addresses because they never
         // have any DestData yet! When adding new DestData, it should be
         // considered here whether to retain or delete it (or move it?).
         if (IsMine(address)) {
             WalletLogPrintf(
                 "%s called with IsMine address, NOT SUPPORTED. Please "
                 "report this bug! %s\n",
                 __func__, PACKAGE_BUGREPORT);
             return false;
         }
         // Delete destdata tuples associated with address
         for (const std::pair<const std::string, std::string> &item :
              m_address_book[address].destdata) {
             batch.EraseDestData(address, item.first);
         }
         m_address_book.erase(address);
         is_mine = IsMine(address) != ISMINE_NO;
     }
 
     NotifyAddressBookChanged(this, address, "", is_mine, "", CT_DELETED);
 
     batch.ErasePurpose(address);
     return batch.EraseName(address);
 }
 
 size_t CWallet::KeypoolCountExternalKeys() const {
     AssertLockHeld(cs_wallet);
 
     unsigned int count = 0;
     for (auto spk_man : GetActiveScriptPubKeyMans()) {
         count += spk_man->KeypoolCountExternalKeys();
     }
 
     return count;
 }
 
 unsigned int CWallet::GetKeyPoolSize() const {
     AssertLockHeld(cs_wallet);
 
     unsigned int count = 0;
     for (auto spk_man : GetActiveScriptPubKeyMans()) {
         count += spk_man->GetKeyPoolSize();
     }
     return count;
 }
 
 bool CWallet::TopUpKeyPool(unsigned int kpSize) {
     LOCK(cs_wallet);
     bool res = true;
     for (auto spk_man : GetActiveScriptPubKeyMans()) {
         res &= spk_man->TopUp(kpSize);
     }
     return res;
 }
 
 bool CWallet::GetNewDestination(const OutputType type, const std::string label,
                                 CTxDestination &dest, std::string &error) {
     LOCK(cs_wallet);
     error.clear();
     bool result = false;
     auto spk_man = GetScriptPubKeyMan(type, false /* internal */);
     if (spk_man) {
         spk_man->TopUp();
         result = spk_man->GetNewDestination(type, dest, error);
     } else {
         error = strprintf("Error: No %s addresses available.",
                           FormatOutputType(type));
     }
     if (result) {
         SetAddressBook(dest, label, "receive");
     }
 
     return result;
 }
 
 bool CWallet::GetNewChangeDestination(const OutputType type,
                                       CTxDestination &dest,
                                       std::string &error) {
     LOCK(cs_wallet);
     error.clear();
 
     ReserveDestination reservedest(this, type);
     if (!reservedest.GetReservedDestination(dest, true)) {
         error = _("Error: Keypool ran out, please call keypoolrefill first")
                     .translated;
         return false;
     }
 
     reservedest.KeepDestination();
     return true;
 }
 
 int64_t CWallet::GetOldestKeyPoolTime() const {
     LOCK(cs_wallet);
     int64_t oldestKey = std::numeric_limits<int64_t>::max();
     for (const auto &spk_man_pair : m_spk_managers) {
         oldestKey =
             std::min(oldestKey, spk_man_pair.second->GetOldestKeyPoolTime());
     }
     return oldestKey;
 }
 
 void CWallet::MarkDestinationsDirty(
     const std::set<CTxDestination> &destinations) {
     for (auto &entry : mapWallet) {
         CWalletTx &wtx = entry.second;
         if (wtx.m_is_cache_empty) {
             continue;
         }
 
         for (size_t i = 0; i < wtx.tx->vout.size(); i++) {
             CTxDestination dst;
 
             if (ExtractDestination(wtx.tx->vout[i].scriptPubKey, dst) &&
                 destinations.count(dst)) {
                 wtx.MarkDirty();
                 break;
             }
         }
     }
 }
 
 std::map<CTxDestination, Amount> CWallet::GetAddressBalances() const {
     std::map<CTxDestination, Amount> balances;
 
     LOCK(cs_wallet);
     std::set<TxId> trusted_parents;
     for (const auto &walletEntry : mapWallet) {
         const CWalletTx &wtx = walletEntry.second;
 
         if (!IsTrusted(wtx, trusted_parents)) {
             continue;
         }
 
         if (wtx.IsImmatureCoinBase()) {
             continue;
         }
 
         int nDepth = wtx.GetDepthInMainChain();
         if (nDepth < (wtx.IsFromMe(ISMINE_ALL) ? 0 : 1)) {
             continue;
         }
 
         for (uint32_t i = 0; i < wtx.tx->vout.size(); i++) {
             CTxDestination addr;
             if (!IsMine(wtx.tx->vout[i])) {
                 continue;
             }
 
             if (!ExtractDestination(wtx.tx->vout[i].scriptPubKey, addr)) {
                 continue;
             }
 
             Amount n = IsSpent(COutPoint(walletEntry.first, i))
                            ? Amount::zero()
                            : wtx.tx->vout[i].nValue;
             balances[addr] += n;
         }
     }
 
     return balances;
 }
 
 std::set<std::set<CTxDestination>> CWallet::GetAddressGroupings() const {
     AssertLockHeld(cs_wallet);
     std::set<std::set<CTxDestination>> groupings;
     std::set<CTxDestination> grouping;
 
     for (const auto &walletEntry : mapWallet) {
         const CWalletTx &wtx = walletEntry.second;
 
         if (wtx.tx->vin.size() > 0) {
             bool any_mine = false;
             // Group all input addresses with each other.
             for (const auto &txin : wtx.tx->vin) {
                 CTxDestination address;
                 // If this input isn't mine, ignore it.
                 if (!IsMine(txin)) {
                     continue;
                 }
 
                 if (!ExtractDestination(mapWallet.at(txin.prevout.GetTxId())
                                             .tx->vout[txin.prevout.GetN()]
                                             .scriptPubKey,
                                         address)) {
                     continue;
                 }
 
                 grouping.insert(address);
                 any_mine = true;
             }
 
             // Group change with input addresses.
             if (any_mine) {
                 for (const auto &txout : wtx.tx->vout) {
                     if (IsChange(txout)) {
                         CTxDestination txoutAddr;
                         if (!ExtractDestination(txout.scriptPubKey,
                                                 txoutAddr)) {
                             continue;
                         }
 
                         grouping.insert(txoutAddr);
                     }
                 }
             }
 
             if (grouping.size() > 0) {
                 groupings.insert(grouping);
                 grouping.clear();
             }
         }
 
         // Group lone addrs by themselves.
         for (const auto &txout : wtx.tx->vout) {
             if (IsMine(txout)) {
                 CTxDestination address;
                 if (!ExtractDestination(txout.scriptPubKey, address)) {
                     continue;
                 }
 
                 grouping.insert(address);
                 groupings.insert(grouping);
                 grouping.clear();
             }
         }
     }
 
     // A set of pointers to groups of addresses.
     std::set<std::set<CTxDestination> *> uniqueGroupings;
     // Map addresses to the unique group containing it.
     std::map<CTxDestination, std::set<CTxDestination> *> setmap;
     for (std::set<CTxDestination> _grouping : groupings) {
         // Make a set of all the groups hit by this new group.
         std::set<std::set<CTxDestination> *> hits;
         std::map<CTxDestination, std::set<CTxDestination> *>::iterator it;
         for (const CTxDestination &address : _grouping) {
             if ((it = setmap.find(address)) != setmap.end()) {
                 hits.insert((*it).second);
             }
         }
 
         // Merge all hit groups into a new single group and delete old groups.
         std::set<CTxDestination> *merged =
             new std::set<CTxDestination>(_grouping);
         for (std::set<CTxDestination> *hit : hits) {
             merged->insert(hit->begin(), hit->end());
             uniqueGroupings.erase(hit);
             delete hit;
         }
         uniqueGroupings.insert(merged);
 
         // Update setmap.
         for (const CTxDestination &element : *merged) {
             setmap[element] = merged;
         }
     }
 
     std::set<std::set<CTxDestination>> ret;
     for (const std::set<CTxDestination> *uniqueGrouping : uniqueGroupings) {
         ret.insert(*uniqueGrouping);
         delete uniqueGrouping;
     }
 
     return ret;
 }
 
 std::set<CTxDestination>
 CWallet::GetLabelAddresses(const std::string &label) const {
     LOCK(cs_wallet);
     std::set<CTxDestination> result;
     for (const std::pair<const CTxDestination, CAddressBookData> &item :
          m_address_book) {
         if (item.second.IsChange()) {
             continue;
         }
         const CTxDestination &address = item.first;
         const std::string &strName = item.second.GetLabel();
         if (strName == label) {
             result.insert(address);
         }
     }
 
     return result;
 }
 
 bool ReserveDestination::GetReservedDestination(CTxDestination &dest,
                                                 bool internal) {
     m_spk_man = pwallet->GetScriptPubKeyMan(type, internal);
     if (!m_spk_man) {
         return false;
     }
 
     if (nIndex == -1) {
         m_spk_man->TopUp();
 
         CKeyPool keypool;
         if (!m_spk_man->GetReservedDestination(type, internal, address, nIndex,
                                                keypool)) {
             return false;
         }
         fInternal = keypool.fInternal;
     }
     dest = address;
     return true;
 }
 
 void ReserveDestination::KeepDestination() {
     if (nIndex != -1) {
         m_spk_man->KeepDestination(nIndex, type);
     }
 
     nIndex = -1;
     address = CNoDestination();
 }
 
 void ReserveDestination::ReturnDestination() {
     if (nIndex != -1) {
         m_spk_man->ReturnDestination(nIndex, fInternal, address);
     }
     nIndex = -1;
     address = CNoDestination();
 }
 
 void CWallet::LockCoin(const COutPoint &output) {
     AssertLockHeld(cs_wallet);
     setLockedCoins.insert(output);
 }
 
 void CWallet::UnlockCoin(const COutPoint &output) {
     AssertLockHeld(cs_wallet);
     setLockedCoins.erase(output);
 }
 
 void CWallet::UnlockAllCoins() {
     AssertLockHeld(cs_wallet);
     setLockedCoins.clear();
 }
 
 bool CWallet::IsLockedCoin(const COutPoint &outpoint) const {
     AssertLockHeld(cs_wallet);
 
     return setLockedCoins.count(outpoint) > 0;
 }
 
 void CWallet::ListLockedCoins(std::vector<COutPoint> &vOutpts) const {
     AssertLockHeld(cs_wallet);
     for (COutPoint outpoint : setLockedCoins) {
         vOutpts.push_back(outpoint);
     }
 }
 
 /** @} */ // end of Actions
 
 void CWallet::GetKeyBirthTimes(std::map<CKeyID, int64_t> &mapKeyBirth) const {
     AssertLockHeld(cs_wallet);
     mapKeyBirth.clear();
 
     LegacyScriptPubKeyMan *spk_man = GetLegacyScriptPubKeyMan();
     assert(spk_man != nullptr);
     LOCK(spk_man->cs_KeyStore);
 
     // Get birth times for keys with metadata.
     for (const auto &entry : spk_man->mapKeyMetadata) {
         if (entry.second.nCreateTime) {
             mapKeyBirth[entry.first] = entry.second.nCreateTime;
         }
     }
 
     // map in which we'll infer heights of other keys
     std::map<CKeyID, const CWalletTx::Confirmation *> mapKeyFirstBlock;
     CWalletTx::Confirmation max_confirm;
     // the tip can be reorganized; use a 144-block safety margin
     max_confirm.block_height =
         GetLastBlockHeight() > 144 ? GetLastBlockHeight() - 144 : 0;
     CHECK_NONFATAL(chain().findAncestorByHeight(
         GetLastBlockHash(), max_confirm.block_height,
         FoundBlock().hash(max_confirm.hashBlock)));
     for (const CKeyID &keyid : spk_man->GetKeys()) {
         if (mapKeyBirth.count(keyid) == 0) {
             mapKeyFirstBlock[keyid] = &max_confirm;
         }
     }
 
     // If there are no such keys, we're done.
     if (mapKeyFirstBlock.empty()) {
         return;
     }
 
     // Find first block that affects those keys, if there are any left.
     for (const auto &entry : mapWallet) {
         // iterate over all wallet transactions...
         const CWalletTx &wtx = entry.second;
         if (wtx.m_confirm.status == CWalletTx::CONFIRMED) {
             // ... which are already in a block
             for (const CTxOut &txout : wtx.tx->vout) {
                 // Iterate over all their outputs...
                 for (const auto &keyid :
                      GetAffectedKeys(txout.scriptPubKey, *spk_man)) {
                     // ... and all their affected keys.
                     auto rit = mapKeyFirstBlock.find(keyid);
                     if (rit != mapKeyFirstBlock.end() &&
                         wtx.m_confirm.block_height <
                             rit->second->block_height) {
                         rit->second = &wtx.m_confirm;
                     }
                 }
             }
         }
     }
 
     // Extract block timestamps for those keys.
     for (const auto &entry : mapKeyFirstBlock) {
         int64_t block_time;
         CHECK_NONFATAL(chain().findBlock(entry.second->hashBlock,
                                          FoundBlock().time(block_time)));
         // block times can be 2h off
         mapKeyBirth[entry.first] = block_time - TIMESTAMP_WINDOW;
     }
 }
 
 /**
  * Compute smart timestamp for a transaction being added to the wallet.
  *
  * Logic:
  * - If sending a transaction, assign its timestamp to the current time.
  * - If receiving a transaction outside a block, assign its timestamp to the
  *   current time.
  * - If receiving a block with a future timestamp, assign all its (not already
  *   known) transactions' timestamps to the current time.
  * - If receiving a block with a past timestamp, before the most recent known
  *   transaction (that we care about), assign all its (not already known)
  *   transactions' timestamps to the same timestamp as that most-recent-known
  *   transaction.
  * - If receiving a block with a past timestamp, but after the most recent known
  *   transaction, assign all its (not already known) transactions' timestamps to
  *   the block time.
  *
  * For more information see CWalletTx::nTimeSmart,
  * https://bitcointalk.org/?topic=54527, or
  * https://github.com/bitcoin/bitcoin/pull/1393.
  */
 unsigned int CWallet::ComputeTimeSmart(const CWalletTx &wtx) const {
     unsigned int nTimeSmart = wtx.nTimeReceived;
     if (!wtx.isUnconfirmed() && !wtx.isAbandoned()) {
         int64_t blocktime;
         if (chain().findBlock(wtx.m_confirm.hashBlock,
                               FoundBlock().time(blocktime))) {
             int64_t latestNow = wtx.nTimeReceived;
             int64_t latestEntry = 0;
 
             // Tolerate times up to the last timestamp in the wallet not more
             // than 5 minutes into the future
             int64_t latestTolerated = latestNow + 300;
             const TxItems &txOrdered = wtxOrdered;
             for (auto it = txOrdered.rbegin(); it != txOrdered.rend(); ++it) {
                 CWalletTx *const pwtx = it->second;
                 if (pwtx == &wtx) {
                     continue;
                 }
                 int64_t nSmartTime;
                 nSmartTime = pwtx->nTimeSmart;
                 if (!nSmartTime) {
                     nSmartTime = pwtx->nTimeReceived;
                 }
                 if (nSmartTime <= latestTolerated) {
                     latestEntry = nSmartTime;
                     if (nSmartTime > latestNow) {
                         latestNow = nSmartTime;
                     }
                     break;
                 }
             }
 
             nTimeSmart = std::max(latestEntry, std::min(blocktime, latestNow));
         } else {
             WalletLogPrintf("%s: found %s in block %s not in index\n", __func__,
                             wtx.GetId().ToString(),
                             wtx.m_confirm.hashBlock.ToString());
         }
     }
     return nTimeSmart;
 }
 
 bool CWallet::AddDestData(WalletBatch &batch, const CTxDestination &dest,
                           const std::string &key, const std::string &value) {
     if (boost::get<CNoDestination>(&dest)) {
         return false;
     }
 
     m_address_book[dest].destdata.insert(std::make_pair(key, value));
     return batch.WriteDestData(dest, key, value);
 }
 
 bool CWallet::EraseDestData(WalletBatch &batch, const CTxDestination &dest,
                             const std::string &key) {
     if (!m_address_book[dest].destdata.erase(key)) {
         return false;
     }
 
     return batch.EraseDestData(dest, key);
 }
 
 void CWallet::LoadDestData(const CTxDestination &dest, const std::string &key,
                            const std::string &value) {
     m_address_book[dest].destdata.insert(std::make_pair(key, value));
 }
 
 bool CWallet::GetDestData(const CTxDestination &dest, const std::string &key,
                           std::string *value) const {
     std::map<CTxDestination, CAddressBookData>::const_iterator i =
         m_address_book.find(dest);
     if (i != m_address_book.end()) {
         CAddressBookData::StringMap::const_iterator j =
             i->second.destdata.find(key);
         if (j != i->second.destdata.end()) {
             if (value) {
                 *value = j->second;
             }
 
             return true;
         }
     }
     return false;
 }
 
 std::vector<std::string>
 CWallet::GetDestValues(const std::string &prefix) const {
     std::vector<std::string> values;
     for (const auto &address : m_address_book) {
         for (const auto &data : address.second.destdata) {
             if (!data.first.compare(0, prefix.size(), prefix)) {
                 values.emplace_back(data.second);
             }
         }
     }
     return values;
 }
 
 std::unique_ptr<WalletDatabase>
 MakeWalletDatabase(const std::string &name, const DatabaseOptions &options,
                    DatabaseStatus &status, bilingual_str &error_string) {
     // Do some checking on wallet path. It should be either a:
     //
     // 1. Path where a directory can be created.
     // 2. Path to an existing directory.
     // 3. Path to a symlink to a directory.
     // 4. For backwards compatibility, the name of a data file in -walletdir.
     const fs::path &wallet_path = fs::absolute(name, GetWalletDir());
     fs::file_type path_type = fs::symlink_status(wallet_path).type();
     if (!(path_type == fs::file_not_found || path_type == fs::directory_file ||
           (path_type == fs::symlink_file && fs::is_directory(wallet_path)) ||
           (path_type == fs::regular_file &&
            fs::path(name).filename() == name))) {
         error_string = Untranslated(
             strprintf("Invalid -wallet path '%s'. -wallet path should point to "
                       "a directory where wallet.dat and "
                       "database/log.?????????? files can be stored, a location "
                       "where such a directory could be created, "
                       "or (for backwards compatibility) the name of an "
                       "existing data file in -walletdir (%s)",
                       name, GetWalletDir()));
         status = DatabaseStatus::FAILED_BAD_PATH;
         return nullptr;
     }
     return MakeDatabase(wallet_path, options, status, error_string);
 }
 
 std::shared_ptr<CWallet>
 CWallet::Create(interfaces::Chain &chain, const std::string &name,
                 std::unique_ptr<WalletDatabase> database,
                 uint64_t wallet_creation_flags, bilingual_str &error,
                 std::vector<bilingual_str> &warnings) {
     const std::string &walletFile = database->Filename();
 
     chain.initMessage(_("Loading wallet...").translated);
 
     int64_t nStart = GetTimeMillis();
     bool fFirstRun = true;
     // TODO: Can't use std::make_shared because we need a custom deleter but
     // should be possible to use std::allocate_shared.
     std::shared_ptr<CWallet> walletInstance(
         new CWallet(&chain, name, std::move(database)), ReleaseWallet);
     DBErrors nLoadWalletRet = walletInstance->LoadWallet(fFirstRun);
     if (nLoadWalletRet != DBErrors::LOAD_OK) {
         if (nLoadWalletRet == DBErrors::CORRUPT) {
             error =
                 strprintf(_("Error loading %s: Wallet corrupted"), walletFile);
             return nullptr;
         }
 
         if (nLoadWalletRet == DBErrors::NONCRITICAL_ERROR) {
             warnings.push_back(
                 strprintf(_("Error reading %s! All keys read correctly, but "
                             "transaction data or address book entries might be "
                             "missing or incorrect."),
                           walletFile));
         } else if (nLoadWalletRet == DBErrors::TOO_NEW) {
             error = strprintf(
                 _("Error loading %s: Wallet requires newer version of %s"),
                 walletFile, PACKAGE_NAME);
             return nullptr;
         } else if (nLoadWalletRet == DBErrors::NEED_REWRITE) {
             error = strprintf(
                 _("Wallet needed to be rewritten: restart %s to complete"),
                 PACKAGE_NAME);
             return nullptr;
         } else {
             error = strprintf(_("Error loading %s"), walletFile);
             return nullptr;
         }
     }
 
     if (fFirstRun) {
         // Ensure this wallet.dat can only be opened by clients supporting
         // HD with chain split and expects no default key.
         walletInstance->SetMinVersion(FEATURE_LATEST);
 
         walletInstance->AddWalletFlags(wallet_creation_flags);
 
         // Only create LegacyScriptPubKeyMan when not descriptor wallet
         if (!walletInstance->IsWalletFlagSet(WALLET_FLAG_DESCRIPTORS)) {
             walletInstance->SetupLegacyScriptPubKeyMan();
         }
 
         if (!(wallet_creation_flags &
               (WALLET_FLAG_DISABLE_PRIVATE_KEYS | WALLET_FLAG_BLANK_WALLET))) {
             LOCK(walletInstance->cs_wallet);
             if (walletInstance->IsWalletFlagSet(WALLET_FLAG_DESCRIPTORS)) {
                 walletInstance->SetupDescriptorScriptPubKeyMans();
                 // SetupDescriptorScriptPubKeyMans already calls SetupGeneration
                 // for us so we don't need to call SetupGeneration separately
             } else {
                 // Legacy wallets need SetupGeneration here.
                 for (auto spk_man :
                      walletInstance->GetActiveScriptPubKeyMans()) {
                     if (!spk_man->SetupGeneration()) {
                         error = _("Unable to generate initial keys");
                         return nullptr;
                     }
                 }
             }
         }
 
         walletInstance->chainStateFlushed(chain.getTipLocator());
     } else if (wallet_creation_flags & WALLET_FLAG_DISABLE_PRIVATE_KEYS) {
         // Make it impossible to disable private keys after creation
         error = strprintf(_("Error loading %s: Private keys can only be "
                             "disabled during creation"),
                           walletFile);
         return nullptr;
     } else if (walletInstance->IsWalletFlagSet(
                    WALLET_FLAG_DISABLE_PRIVATE_KEYS)) {
         for (auto spk_man : walletInstance->GetActiveScriptPubKeyMans()) {
             if (spk_man->HavePrivateKeys()) {
                 warnings.push_back(
                     strprintf(_("Warning: Private keys detected in wallet {%s} "
                                 "with disabled private keys"),
                               walletFile));
             }
         }
     }
 
     if (gArgs.IsArgSet("-mintxfee")) {
         Amount n = Amount::zero();
         if (!ParseMoney(gArgs.GetArg("-mintxfee", ""), n) ||
             n == Amount::zero()) {
             error = AmountErrMsg("mintxfee", gArgs.GetArg("-mintxfee", ""));
             return nullptr;
         }
         if (n > HIGH_TX_FEE_PER_KB) {
             warnings.push_back(AmountHighWarn("-mintxfee") + Untranslated(" ") +
                                _("This is the minimum transaction fee you pay "
                                  "on every transaction."));
         }
         walletInstance->m_min_fee = CFeeRate(n);
     }
 
     if (gArgs.IsArgSet("-maxapsfee")) {
         const std::string max_aps_fee{gArgs.GetArg("-maxapsfee", "")};
         Amount n = Amount::zero();
         if (max_aps_fee == "-1") {
             n = -1 * SATOSHI;
         } else if (!ParseMoney(max_aps_fee, n)) {
             error = AmountErrMsg("maxapsfee", max_aps_fee);
             return nullptr;
         }
         if (n > HIGH_APS_FEE) {
             warnings.push_back(
                 AmountHighWarn("-maxapsfee") + Untranslated(" ") +
                 _("This is the maximum transaction fee you pay (in addition to"
                   " the normal fee) to prioritize partial spend avoidance over"
                   " regular coin selection."));
         }
         walletInstance->m_max_aps_fee = n;
     }
 
     if (gArgs.IsArgSet("-fallbackfee")) {
         Amount nFeePerK = Amount::zero();
         if (!ParseMoney(gArgs.GetArg("-fallbackfee", ""), nFeePerK)) {
             error =
                 strprintf(_("Invalid amount for -fallbackfee=<amount>: '%s'"),
                           gArgs.GetArg("-fallbackfee", ""));
             return nullptr;
         }
         if (nFeePerK > HIGH_TX_FEE_PER_KB) {
             warnings.push_back(AmountHighWarn("-fallbackfee") +
                                Untranslated(" ") +
                                _("This is the transaction fee you may pay when "
                                  "fee estimates are not available."));
         }
         walletInstance->m_fallback_fee = CFeeRate(nFeePerK);
     }
     // Disable fallback fee in case value was set to 0, enable if non-null value
     walletInstance->m_allow_fallback_fee =
         walletInstance->m_fallback_fee.GetFeePerK() != Amount::zero();
 
     if (gArgs.IsArgSet("-paytxfee")) {
         Amount nFeePerK = Amount::zero();
         if (!ParseMoney(gArgs.GetArg("-paytxfee", ""), nFeePerK)) {
             error = AmountErrMsg("paytxfee", gArgs.GetArg("-paytxfee", ""));
             return nullptr;
         }
         if (nFeePerK > HIGH_TX_FEE_PER_KB) {
             warnings.push_back(AmountHighWarn("-paytxfee") + Untranslated(" ") +
                                _("This is the transaction fee you will pay if "
                                  "you send a transaction."));
         }
         walletInstance->m_pay_tx_fee = CFeeRate(nFeePerK, 1000);
         if (walletInstance->m_pay_tx_fee < chain.relayMinFee()) {
             error = strprintf(_("Invalid amount for -paytxfee=<amount>: '%s' "
                                 "(must be at least %s)"),
                               gArgs.GetArg("-paytxfee", ""),
                               chain.relayMinFee().ToString());
             return nullptr;
         }
     }
 
     if (gArgs.IsArgSet("-maxtxfee")) {
         Amount nMaxFee = Amount::zero();
         if (!ParseMoney(gArgs.GetArg("-maxtxfee", ""), nMaxFee)) {
             error = AmountErrMsg("maxtxfee", gArgs.GetArg("-maxtxfee", ""));
             return nullptr;
         }
         if (nMaxFee > HIGH_MAX_TX_FEE) {
             warnings.push_back(_("-maxtxfee is set very high! Fees this large "
                                  "could be paid on a single transaction."));
         }
         if (CFeeRate(nMaxFee, 1000) < chain.relayMinFee()) {
             error = strprintf(
                 _("Invalid amount for -maxtxfee=<amount>: '%s' (must be at "
                   "least the minrelay fee of %s to prevent stuck "
                   "transactions)"),
                 gArgs.GetArg("-maxtxfee", ""), chain.relayMinFee().ToString());
             return nullptr;
         }
         walletInstance->m_default_max_tx_fee = nMaxFee;
     }
 
     if (chain.relayMinFee().GetFeePerK() > HIGH_TX_FEE_PER_KB) {
         warnings.push_back(
             AmountHighWarn("-minrelaytxfee") + Untranslated(" ") +
             _("The wallet will avoid paying less than the minimum relay fee."));
     }
 
     walletInstance->m_spend_zero_conf_change =
         gArgs.GetBoolArg("-spendzeroconfchange", DEFAULT_SPEND_ZEROCONF_CHANGE);
 
     walletInstance->m_default_address_type = DEFAULT_ADDRESS_TYPE;
 
     walletInstance->WalletLogPrintf("Wallet completed loading in %15dms\n",
                                     GetTimeMillis() - nStart);
 
     // Try to top up keypool. No-op if the wallet is locked.
     walletInstance->TopUpKeyPool();
 
     LOCK(walletInstance->cs_wallet);
 
     // Register wallet with validationinterface. It's done before rescan to
     // avoid missing block connections between end of rescan and validation
     // subscribing. Because of wallet lock being hold, block connection
     // notifications are going to be pending on the validation-side until lock
     // release. It's likely to have block processing duplicata (if rescan block
     // range overlaps with notification one) but we guarantee at least than
     // wallet state is correct after notifications delivery. This is temporary
     // until rescan and notifications delivery are unified under same interface.
     walletInstance->m_chain_notifications_handler =
         walletInstance->chain().handleNotifications(walletInstance);
 
     int rescan_height = 0;
     if (!gArgs.GetBoolArg("-rescan", false)) {
         WalletBatch batch(*walletInstance->database);
         CBlockLocator locator;
         if (batch.ReadBestBlock(locator)) {
             if (const std::optional<int> fork_height =
                     chain.findLocatorFork(locator)) {
                 rescan_height = *fork_height;
             }
         }
     }
 
     const std::optional<int> tip_height = chain.getHeight();
     if (tip_height) {
         walletInstance->m_last_block_processed =
             chain.getBlockHash(*tip_height);
         walletInstance->m_last_block_processed_height = *tip_height;
     } else {
         walletInstance->m_last_block_processed.SetNull();
         walletInstance->m_last_block_processed_height = -1;
     }
 
     if (tip_height && *tip_height != rescan_height) {
         // We can't rescan beyond non-pruned blocks, stop and throw an error.
         // This might happen if a user uses an old wallet within a pruned node
         // or if they ran -disablewallet for a longer time, then decided to
         // re-enable
         if (chain.havePruned()) {
             // Exit early and print an error.
             // If a block is pruned after this check, we will load the wallet,
             // but fail the rescan with a generic error.
             int block_height = *tip_height;
             while (block_height > 0 &&
                    chain.haveBlockOnDisk(block_height - 1) &&
                    rescan_height != block_height) {
                 --block_height;
             }
 
             if (rescan_height != block_height) {
                 error = _("Prune: last wallet synchronisation goes beyond "
                           "pruned data. You need to -reindex (download the "
                           "whole blockchain again in case of pruned node)");
                 return nullptr;
             }
         }
 
         chain.initMessage(_("Rescanning...").translated);
         walletInstance->WalletLogPrintf(
             "Rescanning last %i blocks (from block %i)...\n",
             *tip_height - rescan_height, rescan_height);
 
         // No need to read and scan block if block was created before our wallet
         // birthday (as adjusted for block time variability)
         std::optional<int64_t> time_first_key;
         for (auto spk_man : walletInstance->GetAllScriptPubKeyMans()) {
             int64_t time = spk_man->GetTimeFirstKey();
             if (!time_first_key || time < *time_first_key) {
                 time_first_key = time;
             }
         }
         if (time_first_key) {
             if (std::optional<int> first_block =
                     chain.findFirstBlockWithTimeAndHeight(
                         *time_first_key - TIMESTAMP_WINDOW, rescan_height,
                         nullptr)) {
                 rescan_height = *first_block;
             }
         }
 
         {
             WalletRescanReserver reserver(*walletInstance);
             if (!reserver.reserve() ||
                 (ScanResult::SUCCESS !=
                  walletInstance
                      ->ScanForWalletTransactions(
                          chain.getBlockHash(rescan_height), rescan_height,
                          {} /* max height */, reserver, true /* update */)
                      .status)) {
                 error = _("Failed to rescan the wallet during initialization");
                 return nullptr;
             }
         }
         walletInstance->chainStateFlushed(chain.getTipLocator());
         walletInstance->database->IncrementUpdateCounter();
     }
 
     {
         LOCK(cs_wallets);
         for (auto &load_wallet : g_load_wallet_fns) {
             load_wallet(interfaces::MakeWallet(walletInstance));
         }
     }
 
     walletInstance->SetBroadcastTransactions(
         gArgs.GetBoolArg("-walletbroadcast", DEFAULT_WALLETBROADCAST));
 
     walletInstance->WalletLogPrintf("setKeyPool.size() = %u\n",
                                     walletInstance->GetKeyPoolSize());
     walletInstance->WalletLogPrintf("mapWallet.size() = %u\n",
                                     walletInstance->mapWallet.size());
     walletInstance->WalletLogPrintf("m_address_book.size() = %u\n",
                                     walletInstance->m_address_book.size());
 
     return walletInstance;
 }
 
 const CAddressBookData *
 CWallet::FindAddressBookEntry(const CTxDestination &dest,
                               bool allow_change) const {
     const auto &address_book_it = m_address_book.find(dest);
     if (address_book_it == m_address_book.end()) {
         return nullptr;
     }
     if ((!allow_change) && address_book_it->second.IsChange()) {
         return nullptr;
     }
     return &address_book_it->second;
 }
 
 bool CWallet::UpgradeWallet(int version, bilingual_str &error,
                             std::vector<bilingual_str> &warnings) {
     int prev_version = GetVersion();
     int nMaxVersion = version;
     // The -upgradewallet without argument case
     if (nMaxVersion == 0) {
         WalletLogPrintf("Performing wallet upgrade to %i\n", FEATURE_LATEST);
         nMaxVersion = FEATURE_LATEST;
         // permanently upgrade the wallet immediately
         SetMinVersion(FEATURE_LATEST);
     } else {
         WalletLogPrintf("Allowing wallet upgrade up to %i\n", nMaxVersion);
     }
 
     if (nMaxVersion < GetVersion()) {
         error = _("Cannot downgrade wallet");
         return false;
     }
 
     SetMaxVersion(nMaxVersion);
 
     LOCK(cs_wallet);
 
     // Do not upgrade versions to any version between HD_SPLIT and
     // FEATURE_PRE_SPLIT_KEYPOOL unless already supporting HD_SPLIT
     int max_version = GetVersion();
     if (!CanSupportFeature(FEATURE_HD_SPLIT) &&
         max_version >= FEATURE_HD_SPLIT &&
         max_version < FEATURE_PRE_SPLIT_KEYPOOL) {
         error = _("Cannot upgrade a non HD split wallet without upgrading to "
                   "support pre split keypool. Please use version 200300 or no "
                   "version specified.");
         return false;
     }
 
     for (auto spk_man : GetActiveScriptPubKeyMans()) {
         if (!spk_man->Upgrade(prev_version, error)) {
             return false;
         }
     }
 
     return true;
 }
 
 void CWallet::postInitProcess() {
     LOCK(cs_wallet);
 
     // Add wallet transactions that aren't already in a block to mempool.
     // Do this here as mempool requires genesis block to be loaded.
     ReacceptWalletTransactions();
 
     // Update wallet transactions with current mempool transactions.
     chain().requestMempoolTransactions(*this);
 }
 
 bool CWallet::BackupWallet(const std::string &strDest) const {
     return database->Backup(strDest);
 }
 
 CKeyPool::CKeyPool() {
     nTime = GetTime();
     fInternal = false;
     m_pre_split = false;
 }
 
 CKeyPool::CKeyPool(const CPubKey &vchPubKeyIn, bool internalIn) {
     nTime = GetTime();
     vchPubKey = vchPubKeyIn;
     fInternal = internalIn;
     m_pre_split = false;
 }
 
 int CWalletTx::GetDepthInMainChain() const {
     assert(pwallet != nullptr);
     AssertLockHeld(pwallet->cs_wallet);
     if (isUnconfirmed() || isAbandoned()) {
         return 0;
     }
 
     return (pwallet->GetLastBlockHeight() - m_confirm.block_height + 1) *
            (isConflicted() ? -1 : 1);
 }
 
 int CWalletTx::GetBlocksToMaturity() const {
     if (!IsCoinBase()) {
         return 0;
     }
 
     int chain_depth = GetDepthInMainChain();
     // coinbase tx should not be conflicted
     assert(chain_depth >= 0);
     return std::max(0, (COINBASE_MATURITY + 1) - chain_depth);
 }
 
 bool CWalletTx::IsImmatureCoinBase() const {
     // note GetBlocksToMaturity is 0 for non-coinbase tx
     return GetBlocksToMaturity() > 0;
 }
 
 std::vector<OutputGroup>
 CWallet::GroupOutputs(const std::vector<COutput> &outputs, bool single_coin,
                       const size_t max_ancestors) const {
     std::vector<OutputGroup> groups;
     std::map<CTxDestination, OutputGroup> gmap;
     std::set<CTxDestination> full_groups;
 
     for (const auto &output : outputs) {
         if (output.fSpendable) {
             CTxDestination dst;
             CInputCoin input_coin = output.GetInputCoin();
 
             size_t ancestors, descendants;
             chain().getTransactionAncestry(output.tx->GetId(), ancestors,
                                            descendants);
             if (!single_coin &&
                 ExtractDestination(output.tx->tx->vout[output.i].scriptPubKey,
                                    dst)) {
                 auto it = gmap.find(dst);
                 if (it != gmap.end()) {
                     // Limit output groups to no more than
                     // OUTPUT_GROUP_MAX_ENTRIES number of entries, to protect
                     // against inadvertently creating a too-large transaction
                     // when using -avoidpartialspends to prevent breaking
                     // consensus or surprising users with a very high amount of
                     // fees.
                     if (it->second.m_outputs.size() >=
                         OUTPUT_GROUP_MAX_ENTRIES) {
                         groups.push_back(it->second);
                         it->second = OutputGroup{};
                         full_groups.insert(dst);
                     }
                     it->second.Insert(input_coin, output.nDepth,
                                       output.tx->IsFromMe(ISMINE_ALL),
                                       ancestors, descendants);
                 } else {
                     gmap[dst].Insert(input_coin, output.nDepth,
                                      output.tx->IsFromMe(ISMINE_ALL), ancestors,
                                      descendants);
                 }
             } else {
                 groups.emplace_back(input_coin, output.nDepth,
                                     output.tx->IsFromMe(ISMINE_ALL), ancestors,
                                     descendants);
             }
         }
     }
     if (!single_coin) {
         for (auto &it : gmap) {
             auto &group = it.second;
             if (full_groups.count(it.first) > 0) {
                 // Make this unattractive as we want coin selection to avoid it
                 // if possible
                 group.m_ancestors = max_ancestors - 1;
             }
             groups.push_back(group);
         }
     }
     return groups;
 }
 
 bool CWallet::IsCrypted() const {
     return HasEncryptionKeys();
 }
 
 bool CWallet::IsLocked() const {
     if (!IsCrypted()) {
         return false;
     }
     LOCK(cs_wallet);
     return vMasterKey.empty();
 }
 
 bool CWallet::Lock() {
     if (!IsCrypted()) {
         return false;
     }
 
     {
         LOCK(cs_wallet);
         vMasterKey.clear();
     }
 
     NotifyStatusChanged(this);
     return true;
 }
 
 bool CWallet::Unlock(const CKeyingMaterial &vMasterKeyIn, bool accept_no_keys) {
     {
         LOCK(cs_wallet);
         for (const auto &spk_man_pair : m_spk_managers) {
             if (!spk_man_pair.second->CheckDecryptionKey(vMasterKeyIn,
                                                          accept_no_keys)) {
                 return false;
             }
         }
         vMasterKey = vMasterKeyIn;
     }
     NotifyStatusChanged(this);
     return true;
 }
 
 std::set<ScriptPubKeyMan *> CWallet::GetActiveScriptPubKeyMans() const {
     std::set<ScriptPubKeyMan *> spk_mans;
     for (bool internal : {false, true}) {
         for (OutputType t : OUTPUT_TYPES) {
             auto spk_man = GetScriptPubKeyMan(t, internal);
             if (spk_man) {
                 spk_mans.insert(spk_man);
             }
         }
     }
     return spk_mans;
 }
 
 std::set<ScriptPubKeyMan *> CWallet::GetAllScriptPubKeyMans() const {
     std::set<ScriptPubKeyMan *> spk_mans;
     for (const auto &spk_man_pair : m_spk_managers) {
         spk_mans.insert(spk_man_pair.second.get());
     }
     return spk_mans;
 }
 
 ScriptPubKeyMan *CWallet::GetScriptPubKeyMan(const OutputType &type,
                                              bool internal) const {
     const std::map<OutputType, ScriptPubKeyMan *> &spk_managers =
         internal ? m_internal_spk_managers : m_external_spk_managers;
     std::map<OutputType, ScriptPubKeyMan *>::const_iterator it =
         spk_managers.find(type);
     if (it == spk_managers.end()) {
         WalletLogPrintf(
             "%s scriptPubKey Manager for output type %d does not exist\n",
             internal ? "Internal" : "External", static_cast<int>(type));
         return nullptr;
     }
     return it->second;
 }
 
 std::set<ScriptPubKeyMan *>
 CWallet::GetScriptPubKeyMans(const CScript &script,
                              SignatureData &sigdata) const {
     std::set<ScriptPubKeyMan *> spk_mans;
     for (const auto &spk_man_pair : m_spk_managers) {
         if (spk_man_pair.second->CanProvide(script, sigdata)) {
             spk_mans.insert(spk_man_pair.second.get());
         }
     }
     return spk_mans;
 }
 
 ScriptPubKeyMan *CWallet::GetScriptPubKeyMan(const CScript &script) const {
     SignatureData sigdata;
     for (const auto &spk_man_pair : m_spk_managers) {
         if (spk_man_pair.second->CanProvide(script, sigdata)) {
             return spk_man_pair.second.get();
         }
     }
     return nullptr;
 }
 
 ScriptPubKeyMan *CWallet::GetScriptPubKeyMan(const uint256 &id) const {
     if (m_spk_managers.count(id) > 0) {
         return m_spk_managers.at(id).get();
     }
     return nullptr;
 }
 
 std::unique_ptr<SigningProvider>
 CWallet::GetSolvingProvider(const CScript &script) const {
     SignatureData sigdata;
     return GetSolvingProvider(script, sigdata);
 }
 
 std::unique_ptr<SigningProvider>
 CWallet::GetSolvingProvider(const CScript &script,
                             SignatureData &sigdata) const {
     for (const auto &spk_man_pair : m_spk_managers) {
         if (spk_man_pair.second->CanProvide(script, sigdata)) {
             return spk_man_pair.second->GetSolvingProvider(script);
         }
     }
     return nullptr;
 }
 
 LegacyScriptPubKeyMan *CWallet::GetLegacyScriptPubKeyMan() const {
     if (IsWalletFlagSet(WALLET_FLAG_DESCRIPTORS)) {
         return nullptr;
     }
     // Legacy wallets only have one ScriptPubKeyMan which is a
     // LegacyScriptPubKeyMan. Everything in m_internal_spk_managers and
     // m_external_spk_managers point to the same legacyScriptPubKeyMan.
     auto it = m_internal_spk_managers.find(OutputType::LEGACY);
     if (it == m_internal_spk_managers.end()) {
         return nullptr;
     }
     return dynamic_cast<LegacyScriptPubKeyMan *>(it->second);
 }
 
 LegacyScriptPubKeyMan *CWallet::GetOrCreateLegacyScriptPubKeyMan() {
     SetupLegacyScriptPubKeyMan();
     return GetLegacyScriptPubKeyMan();
 }
 
 void CWallet::SetupLegacyScriptPubKeyMan() {
     if (!m_internal_spk_managers.empty() || !m_external_spk_managers.empty() ||
         !m_spk_managers.empty() || IsWalletFlagSet(WALLET_FLAG_DESCRIPTORS)) {
         return;
     }
 
     auto spk_manager =
         std::unique_ptr<ScriptPubKeyMan>(new LegacyScriptPubKeyMan(*this));
     for (const auto &type : OUTPUT_TYPES) {
         m_internal_spk_managers[type] = spk_manager.get();
         m_external_spk_managers[type] = spk_manager.get();
     }
     m_spk_managers[spk_manager->GetID()] = std::move(spk_manager);
 }
 
 const CKeyingMaterial &CWallet::GetEncryptionKey() const {
     return vMasterKey;
 }
 
 bool CWallet::HasEncryptionKeys() const {
     return !mapMasterKeys.empty();
 }
 
 void CWallet::ConnectScriptPubKeyManNotifiers() {
     for (const auto &spk_man : GetActiveScriptPubKeyMans()) {
         spk_man->NotifyWatchonlyChanged.connect(NotifyWatchonlyChanged);
         spk_man->NotifyCanGetAddressesChanged.connect(
             NotifyCanGetAddressesChanged);
     }
 }
 
 void CWallet::LoadDescriptorScriptPubKeyMan(uint256 id,
                                             WalletDescriptor &desc) {
     auto spk_manager = std::unique_ptr<ScriptPubKeyMan>(
         new DescriptorScriptPubKeyMan(*this, desc));
     m_spk_managers[id] = std::move(spk_manager);
 }
 
 void CWallet::SetupDescriptorScriptPubKeyMans() {
     AssertLockHeld(cs_wallet);
 
     // Make a seed
     CKey seed_key;
     seed_key.MakeNewKey(true);
     CPubKey seed = seed_key.GetPubKey();
     assert(seed_key.VerifyPubKey(seed));
 
     // Get the extended key
     CExtKey master_key;
     master_key.SetSeed(seed_key.begin(), seed_key.size());
 
     for (bool internal : {false, true}) {
         for (OutputType t : OUTPUT_TYPES) {
             auto spk_manager =
                 std::make_unique<DescriptorScriptPubKeyMan>(*this, internal);
             if (IsCrypted()) {
                 if (IsLocked()) {
                     throw std::runtime_error(
                         std::string(__func__) +
                         ": Wallet is locked, cannot setup new descriptors");
                 }
                 if (!spk_manager->CheckDecryptionKey(vMasterKey) &&
                     !spk_manager->Encrypt(vMasterKey, nullptr)) {
                     throw std::runtime_error(
                         std::string(__func__) +
                         ": Could not encrypt new descriptors");
                 }
             }
             spk_manager->SetupDescriptorGeneration(master_key, t);
             uint256 id = spk_manager->GetID();
             m_spk_managers[id] = std::move(spk_manager);
             AddActiveScriptPubKeyMan(id, t, internal);
         }
     }
 }
 
 void CWallet::AddActiveScriptPubKeyMan(uint256 id, OutputType type,
                                        bool internal) {
     WalletBatch batch(*database);
     if (!batch.WriteActiveScriptPubKeyMan(static_cast<uint8_t>(type), id,
                                           internal)) {
         throw std::runtime_error(std::string(__func__) +
                                  ": writing active ScriptPubKeyMan id failed");
     }
     LoadActiveScriptPubKeyMan(id, type, internal);
 }
 
 void CWallet::LoadActiveScriptPubKeyMan(uint256 id, OutputType type,
                                         bool internal) {
     WalletLogPrintf(
         "Setting spkMan to active: id = %s, type = %d, internal = %d\n",
         id.ToString(), static_cast<int>(type), static_cast<int>(internal));
     auto &spk_mans =
         internal ? m_internal_spk_managers : m_external_spk_managers;
     auto spk_man = m_spk_managers.at(id).get();
     spk_man->SetInternal(internal);
     spk_mans[type] = spk_man;
 
     NotifyCanGetAddressesChanged();
 }
 
 bool CWallet::IsLegacy() const {
     if (m_internal_spk_managers.count(OutputType::LEGACY) == 0) {
         return false;
     }
     auto spk_man = dynamic_cast<LegacyScriptPubKeyMan *>(
         m_internal_spk_managers.at(OutputType::LEGACY));
     return spk_man != nullptr;
 }
 
 DescriptorScriptPubKeyMan *
 CWallet::GetDescriptorScriptPubKeyMan(const WalletDescriptor &desc) const {
     for (auto &spk_man_pair : m_spk_managers) {
         // Try to downcast to DescriptorScriptPubKeyMan then check if the
         // descriptors match
         DescriptorScriptPubKeyMan *spk_manager =
             dynamic_cast<DescriptorScriptPubKeyMan *>(
                 spk_man_pair.second.get());
         if (spk_manager != nullptr && spk_manager->HasWalletDescriptor(desc)) {
             return spk_manager;
         }
     }
 
     return nullptr;
 }
 
 ScriptPubKeyMan *
 CWallet::AddWalletDescriptor(WalletDescriptor &desc,
                              const FlatSigningProvider &signing_provider,
                              const std::string &label) {
     if (!IsWalletFlagSet(WALLET_FLAG_DESCRIPTORS)) {
         WalletLogPrintf(
             "Cannot add WalletDescriptor to a non-descriptor wallet\n");
         return nullptr;
     }
 
     LOCK(cs_wallet);
     auto new_spk_man = std::make_unique<DescriptorScriptPubKeyMan>(*this, desc);
 
     // If we already have this descriptor, remove it from the maps but add the
     // existing cache to desc
     auto old_spk_man = GetDescriptorScriptPubKeyMan(desc);
     if (old_spk_man) {
         WalletLogPrintf("Update existing descriptor: %s\n",
                         desc.descriptor->ToString());
 
         {
             LOCK(old_spk_man->cs_desc_man);
             new_spk_man->SetCache(old_spk_man->GetWalletDescriptor().cache);
         }
 
         // Remove from maps of active spkMans
         auto old_spk_man_id = old_spk_man->GetID();
         for (bool internal : {false, true}) {
             for (OutputType t : OUTPUT_TYPES) {
                 auto active_spk_man = GetScriptPubKeyMan(t, internal);
                 if (active_spk_man &&
                     active_spk_man->GetID() == old_spk_man_id) {
                     if (internal) {
                         m_internal_spk_managers.erase(t);
                     } else {
                         m_external_spk_managers.erase(t);
                     }
                     break;
                 }
             }
         }
         m_spk_managers.erase(old_spk_man_id);
     }
 
     // Add the private keys to the descriptor
     for (const auto &entry : signing_provider.keys) {
         const CKey &key = entry.second;
         new_spk_man->AddDescriptorKey(key, key.GetPubKey());
     }
 
     // Top up key pool, the manager will generate new scriptPubKeys internally
     new_spk_man->TopUp();
 
     // Apply the label if necessary
     // Note: we disable labels for ranged descriptors
     if (!desc.descriptor->IsRange()) {
         auto script_pub_keys = new_spk_man->GetScriptPubKeys();
         if (script_pub_keys.empty()) {
             WalletLogPrintf(
                 "Could not generate scriptPubKeys (cache is empty)\n");
             return nullptr;
         }
 
         CTxDestination dest;
         if (ExtractDestination(script_pub_keys.at(0), dest)) {
             SetAddressBook(dest, label, "receive");
         }
     }
 
     // Save the descriptor to memory
     auto ret = new_spk_man.get();
     m_spk_managers[new_spk_man->GetID()] = std::move(new_spk_man);
 
     // Save the descriptor to DB
     ret->WriteDescriptor();
 
     return ret;
 }
diff --git a/src/wallet/wallet.h b/src/wallet/wallet.h
index bc6b1d10c..49ba25302 100644
--- a/src/wallet/wallet.h
+++ b/src/wallet/wallet.h
@@ -1,1637 +1,1639 @@
 // Copyright (c) 2009-2010 Satoshi Nakamoto
 // Copyright (c) 2009-2016 The Bitcoin Core developers
 // Copyright (c) 2018-2020 The Bitcoin developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #ifndef BITCOIN_WALLET_WALLET_H
 #define BITCOIN_WALLET_WALLET_H
 
 #include <amount.h>
 #include <interfaces/chain.h>
 #include <interfaces/handler.h>
 #include <outputtype.h>
 #include <primitives/blockhash.h>
 #include <psbt.h>
 #include <tinyformat.h>
 #include <util/message.h>
 #include <util/strencodings.h>
 #include <util/string.h>
 #include <util/system.h>
 #include <util/translation.h>
 #include <util/ui_change_type.h>
 #include <validationinterface.h>
 #include <wallet/coinselection.h>
 #include <wallet/crypter.h>
 #include <wallet/rpcwallet.h>
 #include <wallet/scriptpubkeyman.h>
 #include <wallet/walletdb.h>
 #include <wallet/walletutil.h>
 
 #include <algorithm>
 #include <atomic>
 #include <cstdint>
 #include <map>
 #include <memory>
 #include <optional>
 #include <set>
 #include <stdexcept>
 #include <string>
 #include <utility>
 #include <vector>
 
 #include <boost/signals2/signal.hpp>
 
 using LoadWalletFn =
     std::function<void(std::unique_ptr<interfaces::Wallet> wallet)>;
 
 struct bilingual_str;
 
 //! Explicitly unload and delete the wallet.
 //! Blocks the current thread after signaling the unload intent so that all
 //! wallet clients release the wallet.
 //! Note that, when blocking is not required, the wallet is implicitly unloaded
 //! by the shared pointer deleter.
 void UnloadWallet(std::shared_ptr<CWallet> &&wallet);
 
 bool AddWallet(const std::shared_ptr<CWallet> &wallet);
 bool RemoveWallet(const std::shared_ptr<CWallet> &wallet,
                   std::optional<bool> load_on_start,
                   std::vector<bilingual_str> &warnings);
 bool RemoveWallet(const std::shared_ptr<CWallet> &wallet,
                   std::optional<bool> load_on_start);
 std::vector<std::shared_ptr<CWallet>> GetWallets();
 std::shared_ptr<CWallet> GetWallet(const std::string &name);
 std::shared_ptr<CWallet>
 LoadWallet(interfaces::Chain &chain, const std::string &name,
            std::optional<bool> load_on_start, const DatabaseOptions &options,
            DatabaseStatus &status, bilingual_str &error,
            std::vector<bilingual_str> &warnings);
 std::shared_ptr<CWallet>
 CreateWallet(interfaces::Chain &chain, const std::string &name,
              std::optional<bool> load_on_start, const DatabaseOptions &options,
              DatabaseStatus &status, bilingual_str &error,
              std::vector<bilingual_str> &warnings);
 std::unique_ptr<interfaces::Handler> HandleLoadWallet(LoadWalletFn load_wallet);
 std::unique_ptr<WalletDatabase>
 MakeWalletDatabase(const std::string &name, const DatabaseOptions &options,
                    DatabaseStatus &status, bilingual_str &error);
 
 //! -paytxfee default
 constexpr Amount DEFAULT_PAY_TX_FEE = Amount::zero();
 //! -fallbackfee default
 static const Amount DEFAULT_FALLBACK_FEE = Amount::zero();
 //! -mintxfee default
 static const Amount DEFAULT_TRANSACTION_MINFEE_PER_KB = 1000 * SATOSHI;
 /**
  * maximum fee increase allowed to do partial spend avoidance, even for nodes
  * with this feature disabled by default
  *
  * A value of -1 disables this feature completely.
  * A value of 0 (current default) means to attempt to do partial spend
  * avoidance, and use its results if the fees remain *unchanged* A value > 0
  * means to do partial spend avoidance if the fee difference against a regular
  * coin selection instance is in the range [0..value].
  */
 static const Amount DEFAULT_MAX_AVOIDPARTIALSPEND_FEE = Amount::zero();
 //! discourage APS fee higher than this amount
 constexpr Amount HIGH_APS_FEE{COIN / 10000};
 //! minimum recommended increment for BIP 125 replacement txs
 static const Amount WALLET_INCREMENTAL_RELAY_FEE(5000 * SATOSHI);
 //! Default for -spendzeroconfchange
 static const bool DEFAULT_SPEND_ZEROCONF_CHANGE = true;
 //! Default for -walletrejectlongchains
 static const bool DEFAULT_WALLET_REJECT_LONG_CHAINS = false;
 static const bool DEFAULT_WALLETBROADCAST = true;
 static const bool DEFAULT_DISABLE_WALLET = false;
 //! -maxtxfee default
 constexpr Amount DEFAULT_TRANSACTION_MAXFEE{COIN / 10};
 //! Discourage users to set fees higher than this amount (in satoshis) per kB
 constexpr Amount HIGH_TX_FEE_PER_KB{COIN / 100};
 //! -maxtxfee will warn if called with a higher fee than this amount (in
 //! satoshis)
 constexpr Amount HIGH_MAX_TX_FEE{100 * HIGH_TX_FEE_PER_KB};
 //! Pre-calculated constants for input size estimation
 static constexpr size_t DUMMY_P2PKH_INPUT_SIZE = 148;
 
 class CChainParams;
 class CCoinControl;
 class COutput;
 class CScript;
 class CTxMemPool;
 class CWalletTx;
 class ReserveDestination;
 
 //! Default for -addresstype
 constexpr OutputType DEFAULT_ADDRESS_TYPE{OutputType::LEGACY};
 
 static constexpr uint64_t KNOWN_WALLET_FLAGS =
     WALLET_FLAG_AVOID_REUSE | WALLET_FLAG_BLANK_WALLET |
     WALLET_FLAG_KEY_ORIGIN_METADATA | WALLET_FLAG_DISABLE_PRIVATE_KEYS |
     WALLET_FLAG_DESCRIPTORS;
 
 static constexpr uint64_t MUTABLE_WALLET_FLAGS = WALLET_FLAG_AVOID_REUSE;
 
 static const std::map<std::string, WalletFlags> WALLET_FLAG_MAP{
     {"avoid_reuse", WALLET_FLAG_AVOID_REUSE},
     {"blank", WALLET_FLAG_BLANK_WALLET},
     {"key_origin_metadata", WALLET_FLAG_KEY_ORIGIN_METADATA},
     {"disable_private_keys", WALLET_FLAG_DISABLE_PRIVATE_KEYS},
     {"descriptor_wallet", WALLET_FLAG_DESCRIPTORS},
 };
 
 extern const std::map<uint64_t, std::string> WALLET_FLAG_CAVEATS;
 
 /**
  * A wrapper to reserve an address from a wallet
  *
  * ReserveDestination is used to reserve an address.
  * It is currently only used inside of CreateTransaction.
  *
  * Instantiating a ReserveDestination does not reserve an address. To do so,
  * GetReservedDestination() needs to be called on the object. Once an address
  * has been reserved, call KeepDestination() on the ReserveDestination object to
  * make sure it is not returned. Call ReturnDestination() to return the address
  * so it can be re-used (for example, if the address was used in a new
  * transaction and that transaction was not completed and needed to be aborted).
  *
  * If an address is reserved and KeepDestination() is not called, then the
  * address will be returned when the ReserveDestination goes out of scope.
  */
 class ReserveDestination {
 protected:
     //! The wallet to reserve from
     const CWallet *const pwallet;
     //! The ScriptPubKeyMan to reserve from. Based on type when
     //! GetReservedDestination is called
     ScriptPubKeyMan *m_spk_man{nullptr};
     OutputType const type;
     //! The index of the address's key in the keypool
     int64_t nIndex{-1};
     //! The destination
     CTxDestination address;
     //! Whether this is from the internal (change output) keypool
     bool fInternal{false};
 
 public:
     //! Construct a ReserveDestination object. This does NOT reserve an address
     //! yet
     explicit ReserveDestination(CWallet *_pwallet, OutputType _type)
         : pwallet(_pwallet), type(_type) {}
 
     ReserveDestination(const ReserveDestination &) = delete;
     ReserveDestination &operator=(const ReserveDestination &) = delete;
 
     //! Destructor. If a key has been reserved and not KeepKey'ed, it will be
     //! returned to the keypool
     ~ReserveDestination() { ReturnDestination(); }
 
     //! Reserve an address
     bool GetReservedDestination(CTxDestination &pubkey, bool internal);
     //! Return reserved address
     void ReturnDestination();
     //! Keep the address. Do not return it's key to the keypool when this object
     //! goes out of scope
     void KeepDestination();
 };
 
 /** Address book data */
 class CAddressBookData {
 private:
     bool m_change{true};
     std::string m_label;
 
 public:
     std::string purpose;
 
     CAddressBookData() : purpose("unknown") {}
 
     typedef std::map<std::string, std::string> StringMap;
     StringMap destdata;
 
     bool IsChange() const { return m_change; }
     const std::string &GetLabel() const { return m_label; }
     void SetLabel(const std::string &label) {
         m_change = false;
         m_label = label;
     }
 };
 
 struct CRecipient {
     CScript scriptPubKey;
     Amount nAmount;
     bool fSubtractFeeFromAmount;
 };
 
 typedef std::map<std::string, std::string> mapValue_t;
 
 static inline void ReadOrderPos(int64_t &nOrderPos, mapValue_t &mapValue) {
     if (!mapValue.count("n")) {
         // TODO: calculate elsewhere
         nOrderPos = -1;
         return;
     }
 
     nOrderPos = atoi64(mapValue["n"]);
 }
 
 static inline void WriteOrderPos(const int64_t &nOrderPos,
                                  mapValue_t &mapValue) {
     if (nOrderPos == -1) {
         return;
     }
     mapValue["n"] = ToString(nOrderPos);
 }
 
 struct COutputEntry {
     CTxDestination destination;
     Amount amount;
     int vout;
 };
 
 /**
  * Legacy class used for deserializing vtxPrev for backwards compatibility.
  * vtxPrev was removed in commit 93a18a3650292afbb441a47d1fa1b94aeb0164e3,
  * but old wallet.dat files may still contain vtxPrev vectors of CMerkleTxs.
  * These need to get deserialized for field alignment when deserializing
  * a CWalletTx, but the deserialized values are discarded.
  */
 class CMerkleTx {
 public:
     template <typename Stream> void Unserialize(Stream &s) {
         CTransactionRef tx;
         BlockHash hashBlock;
         std::vector<uint256> vMerkleBranch;
         int nIndex = 0;
 
         s >> tx >> hashBlock >> vMerkleBranch >> nIndex;
     }
 };
 
 // Get the marginal bytes of spending the specified output
 int CalculateMaximumSignedInputSize(const CTxOut &txout, const CWallet *pwallet,
                                     bool use_max_sig = false);
 
 /**
  * A transaction with a bunch of additional info that only the owner cares
  * about. It includes any unrecorded transactions needed to link it back to the
  * block chain.
  */
 class CWalletTx {
 private:
     const CWallet *const pwallet;
 
     /**
      * Constant used in hashBlock to indicate tx has been abandoned, only used
      * at serialization/deserialization to avoid ambiguity with conflicted.
      */
     static constexpr const uint256 &ABANDON_HASH = uint256::ONE;
 
 public:
     /**
      * Key/value map with information about the transaction.
      *
      * The following keys can be read and written through the map and are
      * serialized in the wallet database:
      *
      *     "comment", "to"   - comment strings provided to sendtoaddress,
      *                         and sendmany wallet RPCs
      *     "replaces_txid"   - txid (as HexStr) of transaction replaced by
      *                         bumpfee on transaction created by bumpfee
      *     "replaced_by_txid" - txid (as HexStr) of transaction created by
      *                         bumpfee on transaction replaced by bumpfee
      *     "from", "message" - obsolete fields that could be set in UI prior to
      *                         2011 (removed in commit 4d9b223)
      *
      * The following keys are serialized in the wallet database, but shouldn't
      * be read or written through the map (they will be temporarily added and
      * removed from the map during serialization):
      *
      *     "fromaccount"     - serialized strFromAccount value
      *     "n"               - serialized nOrderPos value
      *     "timesmart"       - serialized nTimeSmart value
      *     "spent"           - serialized vfSpent value that existed prior to
      *                         2014 (removed in commit 93a18a3)
      */
     mapValue_t mapValue;
     std::vector<std::pair<std::string, std::string>> vOrderForm;
     unsigned int fTimeReceivedIsTxTime;
     //! time received by this node
     unsigned int nTimeReceived;
     /**
      * Stable timestamp that never changes, and reflects the order a transaction
      * was added to the wallet. Timestamp is based on the block time for a
      * transaction added as part of a block, or else the time when the
      * transaction was received if it wasn't part of a block, with the timestamp
      * adjusted in both cases so timestamp order matches the order transactions
      * were added to the wallet. More details can be found in
      * CWallet::ComputeTimeSmart().
      */
     unsigned int nTimeSmart;
     /**
      * From me flag is set to 1 for transactions that were created by the wallet
      * on this bitcoin node, and set to 0 for transactions that were created
      * externally and came in through the network or sendrawtransaction RPC.
      */
     bool fFromMe;
     //! position in ordered transaction list
     int64_t nOrderPos;
     std::multimap<int64_t, CWalletTx *>::const_iterator m_it_wtxOrdered;
 
     // memory only
     enum AmountType {
         DEBIT,
         CREDIT,
         IMMATURE_CREDIT,
         AVAILABLE_CREDIT,
         AMOUNTTYPE_ENUM_ELEMENTS
     };
     Amount GetCachableAmount(AmountType type, const isminefilter &filter,
                              bool recalculate = false) const;
     mutable CachableAmount m_amounts[AMOUNTTYPE_ENUM_ELEMENTS];
     /**
      * This flag is true if all m_amounts caches are empty. This is particularly
      * useful in places where MarkDirty is conditionally called and the
      * condition can be expensive and thus can be skipped if the flag is true.
      * See MarkDestinationsDirty.
      */
     mutable bool m_is_cache_empty{true};
     mutable bool fChangeCached;
     mutable bool fInMempool;
     mutable Amount nChangeCached;
 
     CWalletTx(const CWallet *wallet, CTransactionRef arg)
         : pwallet(wallet), tx(std::move(arg)) {
         Init();
     }
 
     void Init() {
         mapValue.clear();
         vOrderForm.clear();
         fTimeReceivedIsTxTime = false;
         nTimeReceived = 0;
         nTimeSmart = 0;
         fFromMe = false;
         fChangeCached = false;
         fInMempool = false;
         nChangeCached = Amount::zero();
         nOrderPos = -1;
         m_confirm = Confirmation{};
     }
 
     CTransactionRef tx;
 
     /**
      * New transactions start as UNCONFIRMED. At BlockConnected,
      * they will transition to CONFIRMED. In case of reorg, at
      * BlockDisconnected, they roll back to UNCONFIRMED. If we detect a
      * conflicting transaction at block connection, we update conflicted tx and
      * its dependencies as CONFLICTED. If tx isn't confirmed and outside of
      * mempool, the user may switch it to ABANDONED by using the
      * abandontransaction call. This last status may be override by a CONFLICTED
      * or CONFIRMED transition.
      */
     enum Status { UNCONFIRMED, CONFIRMED, CONFLICTED, ABANDONED };
 
     /**
      * Confirmation includes tx status and a triplet of {block height/block
      * hash/tx index in block} at which tx has been confirmed. All three are set
      * to 0 if tx is unconfirmed or abandoned. Meaning of these fields changes
      * with CONFLICTED state where they instead point to block hash and block
      * height of the deepest conflicting tx.
      */
     struct Confirmation {
         Status status;
         int block_height;
         BlockHash hashBlock;
         int nIndex;
         Confirmation(Status s = UNCONFIRMED, int b = 0,
                      BlockHash h = BlockHash(), int i = 0)
             : status(s), block_height(b), hashBlock(h), nIndex(i) {}
     };
 
     Confirmation m_confirm;
 
     template <typename Stream> void Serialize(Stream &s) const {
         mapValue_t mapValueCopy = mapValue;
 
         mapValueCopy["fromaccount"] = "";
         WriteOrderPos(nOrderPos, mapValueCopy);
         if (nTimeSmart) {
             mapValueCopy["timesmart"] = strprintf("%u", nTimeSmart);
         }
 
         //! Used to be vMerkleBranch
         std::vector<char> dummy_vector1;
         //! Used to be vtxPrev
         std::vector<char> dummy_vector2;
         //! Used to be fSpent
         bool dummy_bool = false;
         uint256 serializedHash =
             isAbandoned() ? ABANDON_HASH : m_confirm.hashBlock;
         int serializedIndex =
             isAbandoned() || isConflicted() ? -1 : m_confirm.nIndex;
         s << tx << serializedHash << dummy_vector1 << serializedIndex
           << dummy_vector2 << mapValueCopy << vOrderForm
           << fTimeReceivedIsTxTime << nTimeReceived << fFromMe << dummy_bool;
     }
 
     template <typename Stream> void Unserialize(Stream &s) {
         Init();
 
         //! Used to be vMerkleBranch
         std::vector<uint256> dummy_vector1;
         //! Used to be vtxPrev
         std::vector<CMerkleTx> dummy_vector2;
         //! Used to be fSpent
         bool dummy_bool;
         int serializedIndex;
         s >> tx >> m_confirm.hashBlock >> dummy_vector1 >> serializedIndex >>
             dummy_vector2 >> mapValue >> vOrderForm >> fTimeReceivedIsTxTime >>
             nTimeReceived >> fFromMe >> dummy_bool;
 
         /*
          * At serialization/deserialization, an nIndex == -1 means that
          * hashBlock refers to the earliest block in the chain we know this or
          * any in-wallet ancestor conflicts with. If nIndex == -1 and hashBlock
          * is ABANDON_HASH, it means transaction is abandoned. In same context,
          * an nIndex >= 0 refers to a confirmed transaction (if hashBlock set)
          * or unconfirmed one. Older clients interpret nIndex == -1 as
          * unconfirmed for backward compatibility (pre-commit 9ac63d6).
          */
         if (serializedIndex == -1 && m_confirm.hashBlock == ABANDON_HASH) {
             setAbandoned();
         } else if (serializedIndex == -1) {
             setConflicted();
         } else if (!m_confirm.hashBlock.IsNull()) {
             m_confirm.nIndex = serializedIndex;
             setConfirmed();
         }
 
         ReadOrderPos(nOrderPos, mapValue);
         nTimeSmart = mapValue.count("timesmart")
                          ? (unsigned int)atoi64(mapValue["timesmart"])
                          : 0;
 
         mapValue.erase("fromaccount");
         mapValue.erase("spent");
         mapValue.erase("n");
         mapValue.erase("timesmart");
     }
 
     void SetTx(CTransactionRef arg) { tx = std::move(arg); }
 
     //! make sure balances are recalculated
     void MarkDirty() {
         m_amounts[DEBIT].Reset();
         m_amounts[CREDIT].Reset();
         m_amounts[IMMATURE_CREDIT].Reset();
         m_amounts[AVAILABLE_CREDIT].Reset();
         fChangeCached = false;
         m_is_cache_empty = true;
     }
 
     //! filter decides which addresses will count towards the debit
     Amount GetDebit(const isminefilter &filter) const;
     Amount GetCredit(const isminefilter &filter) const;
     Amount GetImmatureCredit(bool fUseCache = true) const;
     // TODO: Remove "NO_THREAD_SAFETY_ANALYSIS" and replace it with the correct
     // annotation "EXCLUSIVE_LOCKS_REQUIRED(pwallet->cs_wallet)". The
     // annotation "NO_THREAD_SAFETY_ANALYSIS" was temporarily added to avoid
     // having to resolve the issue of member access into incomplete type
     // CWallet.
     Amount GetAvailableCredit(bool fUseCache = true,
                               const isminefilter &filter = ISMINE_SPENDABLE)
         const NO_THREAD_SAFETY_ANALYSIS;
     Amount GetImmatureWatchOnlyCredit(const bool fUseCache = true) const;
     Amount GetChange() const;
 
     // Get the marginal bytes if spending the specified output from this
     // transaction
     int GetSpendSize(unsigned int out, bool use_max_sig = false) const {
         return CalculateMaximumSignedInputSize(tx->vout[out], pwallet,
                                                use_max_sig);
     }
 
     void GetAmounts(std::list<COutputEntry> &listReceived,
                     std::list<COutputEntry> &listSent, Amount &nFee,
                     const isminefilter &filter) const;
 
     bool IsFromMe(const isminefilter &filter) const {
         return GetDebit(filter) > Amount::zero();
     }
 
     // True if only scriptSigs are different
     bool IsEquivalentTo(const CWalletTx &tx) const;
 
     bool InMempool() const;
     bool IsTrusted() const;
 
     int64_t GetTxTime() const;
 
     // Pass this transaction to node for mempool insertion and relay to peers if
     // flag set to true
     bool SubmitMemoryPoolAndRelay(std::string &err_string, bool relay);
 
     // TODO: Remove "NO_THREAD_SAFETY_ANALYSIS" and replace it with the correct
     // annotation "EXCLUSIVE_LOCKS_REQUIRED(pwallet->cs_wallet)". The annotation
     // "NO_THREAD_SAFETY_ANALYSIS" was temporarily added to avoid having to
     // resolve the issue of member access into incomplete type CWallet. Note
     // that we still have the runtime check "AssertLockHeld(pwallet->cs_wallet)"
     // in place.
     std::set<TxId> GetConflicts() const NO_THREAD_SAFETY_ANALYSIS;
 
     /**
      * Return depth of transaction in blockchain:
      * <0  : conflicts with a transaction this deep in the blockchain
      *  0  : in memory pool, waiting to be included in a block
      * >=1 : this many blocks deep in the main chain
      */
     // TODO: Remove "NO_THREAD_SAFETY_ANALYSIS" and replace it with the correct
     // annotation "EXCLUSIVE_LOCKS_REQUIRED(pwallet->cs_wallet)". The annotation
     // "NO_THREAD_SAFETY_ANALYSIS" was temporarily added to avoid having to
     // resolve the issue of member access into incomplete type CWallet. Note
     // that we still have the runtime check "AssertLockHeld(pwallet->cs_wallet)"
     // in place.
     int GetDepthInMainChain() const NO_THREAD_SAFETY_ANALYSIS;
     bool IsInMainChain() const { return GetDepthInMainChain() > 0; }
 
     /**
      * @return number of blocks to maturity for this transaction:
      *  0 : is not a coinbase transaction, or is a mature coinbase transaction
      * >0 : is a coinbase transaction which matures in this many blocks
      */
     int GetBlocksToMaturity() const;
     bool isAbandoned() const {
         return m_confirm.status == CWalletTx::ABANDONED;
     }
     void setAbandoned() {
         m_confirm.status = CWalletTx::ABANDONED;
         m_confirm.hashBlock = BlockHash();
         m_confirm.block_height = 0;
         m_confirm.nIndex = 0;
     }
     bool isConflicted() const {
         return m_confirm.status == CWalletTx::CONFLICTED;
     }
     void setConflicted() { m_confirm.status = CWalletTx::CONFLICTED; }
     bool isUnconfirmed() const {
         return m_confirm.status == CWalletTx::UNCONFIRMED;
     }
     void setUnconfirmed() { m_confirm.status = CWalletTx::UNCONFIRMED; }
     bool isConfirmed() const {
         return m_confirm.status == CWalletTx::CONFIRMED;
     }
     void setConfirmed() { m_confirm.status = CWalletTx::CONFIRMED; }
     TxId GetId() const { return tx->GetId(); }
     bool IsCoinBase() const { return tx->IsCoinBase(); }
     bool IsImmatureCoinBase() const;
 
     // Disable copying of CWalletTx objects to prevent bugs where instances get
     // copied in and out of the mapWallet map, and fields are updated in the
     // wrong copy.
     CWalletTx(CWalletTx const &) = delete;
     void operator=(CWalletTx const &x) = delete;
 };
 
 class COutput {
 public:
     const CWalletTx *tx;
     int i;
     int nDepth;
 
     /**
      * Pre-computed estimated size of this output as a fully-signed input in a
      * transaction. Can be -1 if it could not be calculated.
      */
     int nInputBytes;
 
     /** Whether we have the private keys to spend this output */
     bool fSpendable;
 
     /** Whether we know how to spend this output, ignoring the lack of keys */
     bool fSolvable;
 
     /**
      * Whether to use the maximum sized, 72 byte signature when calculating the
      * size of the input spend. This should only be set when watch-only outputs
      * are allowed.
      */
     bool use_max_sig;
 
     /**
      * Whether this output is considered safe to spend. Unconfirmed transactions
      * from outside keys are considered unsafe and will not be used to fund new
      * spending transactions.
      */
     bool fSafe;
 
     COutput(const CWalletTx *txIn, int iIn, int nDepthIn, bool fSpendableIn,
             bool fSolvableIn, bool fSafeIn, bool use_max_sig_in = false) {
         tx = txIn;
         i = iIn;
         nDepth = nDepthIn;
         fSpendable = fSpendableIn;
         fSolvable = fSolvableIn;
         fSafe = fSafeIn;
         nInputBytes = -1;
         use_max_sig = use_max_sig_in;
         // If known and signable by the given wallet, compute nInputBytes
         // Failure will keep this value -1
         if (fSpendable && tx) {
             nInputBytes = tx->GetSpendSize(i, use_max_sig);
         }
     }
 
     std::string ToString() const;
 
     inline CInputCoin GetInputCoin() const {
         return CInputCoin(tx->tx, i, nInputBytes);
     }
 };
 
 struct CoinSelectionParams {
     bool use_bnb = true;
     size_t change_output_size = 0;
     size_t change_spend_size = 0;
     CFeeRate effective_fee = CFeeRate(Amount::zero());
     size_t tx_noinputs_size = 0;
     //! Indicate that we are subtracting the fee from outputs
     bool m_subtract_fee_outputs = false;
 
     CoinSelectionParams(bool use_bnb_, size_t change_output_size_,
                         size_t change_spend_size_, CFeeRate effective_fee_,
                         size_t tx_noinputs_size_)
         : use_bnb(use_bnb_), change_output_size(change_output_size_),
           change_spend_size(change_spend_size_), effective_fee(effective_fee_),
           tx_noinputs_size(tx_noinputs_size_) {}
     CoinSelectionParams() {}
 };
 
 // forward declarations for ScanForWalletTransactions/RescanFromTime
 class WalletRescanReserver;
 
 /**
  * A CWallet maintains a set of transactions and balances, and provides the
  * ability to create new transactions.
  */
 class CWallet final : public WalletStorage,
                       public interfaces::Chain::Notifications {
 private:
     CKeyingMaterial vMasterKey GUARDED_BY(cs_wallet);
 
     bool Unlock(const CKeyingMaterial &vMasterKeyIn,
                 bool accept_no_keys = false);
 
     std::atomic<bool> fAbortRescan{false};
     // controlled by WalletRescanReserver
     std::atomic<bool> fScanningWallet{false};
     std::atomic<int64_t> m_scanning_start{0};
     std::atomic<double> m_scanning_progress{0};
     friend class WalletRescanReserver;
 
     //! the current wallet version: clients below this version are not able to
     //! load the wallet
     int nWalletVersion GUARDED_BY(cs_wallet) = FEATURE_BASE;
 
     //! the maximum wallet format version: memory-only variable that specifies
     //! to what version this wallet may be upgraded
     int nWalletMaxVersion GUARDED_BY(cs_wallet) = FEATURE_BASE;
 
     int64_t nNextResend = 0;
     bool fBroadcastTransactions = false;
     // Local time that the tip block was received. Used to schedule wallet
     // rebroadcasts.
     std::atomic<int64_t> m_best_block_time{0};
 
     /**
      * Used to keep track of spent outpoints, and detect and report conflicts
      * (double-spends or mutated transactions where the mutant gets mined).
      */
     typedef std::multimap<COutPoint, TxId> TxSpends;
     TxSpends mapTxSpends GUARDED_BY(cs_wallet);
     void AddToSpends(const COutPoint &outpoint, const TxId &wtxid)
         EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
     void AddToSpends(const TxId &wtxid) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
 
     /**
      * Add a transaction to the wallet, or update it. pIndex and posInBlock
      * should be set when the transaction was known to be included in a
      * block. When *pIndex == nullptr, then wallet state is not updated in
      * AddToWallet, but notifications happen and cached balances are marked
      * dirty.
      *
      * If fUpdate is true, existing transactions will be updated.
      * TODO: One exception to this is that the abandoned state is cleared under
      * the assumption that any further notification of a transaction that was
      * considered abandoned is an indication that it is not safe to be
      * considered abandoned. Abandoned state should probably be more carefully
      * tracked via different posInBlock signals or by checking mempool presence
      * when necessary.
      */
     bool AddToWalletIfInvolvingMe(const CTransactionRef &tx,
                                   CWalletTx::Confirmation confirm, bool fUpdate)
         EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
 
     /**
      * Mark a transaction (and its in-wallet descendants) as conflicting with a
      * particular block.
      */
     void MarkConflicted(const BlockHash &hashBlock, int conflicting_height,
                         const TxId &txid);
 
     /**
      * Mark a transaction's inputs dirty, thus forcing the outputs to be
      * recomputed
      */
     void MarkInputsDirty(const CTransactionRef &tx)
         EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
 
     void SyncMetaData(std::pair<TxSpends::iterator, TxSpends::iterator>)
         EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
 
     /**
      * Used by
      * TransactionAddedToMemorypool/BlockConnected/Disconnected/ScanForWalletTransactions.
      * Should be called with non-zero block_hash and posInBlock if this is for a
      * transaction that is included in a block.
      */
     void SyncTransaction(const CTransactionRef &tx,
                          CWalletTx::Confirmation confirm, bool update_tx = true)
         EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
 
     std::atomic<uint64_t> m_wallet_flags{0};
 
     bool SetAddressBookWithDB(WalletBatch &batch, const CTxDestination &address,
                               const std::string &strName,
                               const std::string &strPurpose);
 
     //! Unsets a wallet flag and saves it to disk
     void UnsetWalletFlagWithDB(WalletBatch &batch, uint64_t flag);
 
     //! Unset the blank wallet flag and saves it to disk
     void UnsetBlankWalletFlag(WalletBatch &batch) override;
 
     /** Interface for accessing chain state. */
     interfaces::Chain *m_chain;
 
     /** Wallet name: relative directory name or "" for default wallet. */
     std::string m_name;
 
     /** Internal database handle. */
     std::unique_ptr<WalletDatabase> database;
 
     /**
      * The following is used to keep track of how far behind the wallet is
      * from the chain sync, and to allow clients to block on us being caught up.
      *
      * Processed hash is a pointer on node's tip and doesn't imply that the
      * wallet has scanned sequentially all blocks up to this one.
      */
     BlockHash m_last_block_processed GUARDED_BY(cs_wallet);
 
     /* Height of last block processed is used by wallet to know depth of
      * transactions without relying on Chain interface beyond asynchronous
      * updates. For safety, we initialize it to -1. Height is a pointer on
      * node's tip and doesn't imply that the wallet has scanned sequentially all
      * blocks up to this one.
      */
     int m_last_block_processed_height GUARDED_BY(cs_wallet) = -1;
 
     bool CreateTransactionInternal(const std::vector<CRecipient> &vecSend,
                                    CTransactionRef &tx, Amount &nFeeRet,
                                    int &nChangePosInOut, bilingual_str &error,
                                    const CCoinControl &coin_control, bool sign);
 
     std::map<OutputType, ScriptPubKeyMan *> m_external_spk_managers;
     std::map<OutputType, ScriptPubKeyMan *> m_internal_spk_managers;
 
     // Indexed by a unique identifier produced by each ScriptPubKeyMan using
     // ScriptPubKeyMan::GetID. In many cases it will be the hash of an internal
     // structure
     std::map<uint256, std::unique_ptr<ScriptPubKeyMan>> m_spk_managers;
 
 public:
     /*
      * Main wallet lock.
      * This lock protects all the fields added by CWallet.
      */
     mutable RecursiveMutex cs_wallet;
 
     /**
      * Get database handle used by this wallet. Ideally this function would not
      * be necessary.
      */
     WalletDatabase &GetDBHandle() { return *database; }
     WalletDatabase &GetDatabase() override { return *database; }
 
     /**
      * Select a set of coins such that nValueRet >= nTargetValue and at least
      * all coins from coinControl are selected; Never select unconfirmed coins
      * if they are not ours.
      */
     bool SelectCoins(const std::vector<COutput> &vAvailableCoins,
                      const Amount nTargetValue,
                      std::set<CInputCoin> &setCoinsRet, Amount &nValueRet,
                      const CCoinControl &coin_control,
                      CoinSelectionParams &coin_selection_params,
                      bool &bnb_used) const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
 
     /**
      * Get a name for this wallet for logging/debugging purposes.
      */
     const std::string &GetName() const { return m_name; }
 
     typedef std::map<unsigned int, CMasterKey> MasterKeyMap;
     MasterKeyMap mapMasterKeys;
     unsigned int nMasterKeyMaxID = 0;
 
     /** Construct wallet with specified name and database implementation. */
     CWallet(interfaces::Chain *chain, const std::string &name,
             std::unique_ptr<WalletDatabase> _database)
         : m_chain(chain), m_name(name), database(std::move(_database)) {}
 
     ~CWallet() {
         // Should not have slots connected at this point.
         assert(NotifyUnload.empty());
     }
 
     /* Returns the chain params used by this wallet. */
     const CChainParams &GetChainParams() const override;
 
     bool IsCrypted() const;
     bool IsLocked() const override;
     bool Lock();
 
     /** Interface to assert chain access */
     bool HaveChain() const { return m_chain ? true : false; }
 
     std::map<TxId, CWalletTx> mapWallet GUARDED_BY(cs_wallet);
 
     typedef std::multimap<int64_t, CWalletTx *> TxItems;
     TxItems wtxOrdered;
 
     int64_t nOrderPosNext GUARDED_BY(cs_wallet) = 0;
     uint64_t nAccountingEntryNumber = 0;
 
     std::map<CTxDestination, CAddressBookData>
         m_address_book GUARDED_BY(cs_wallet);
     const CAddressBookData *
     FindAddressBookEntry(const CTxDestination &,
                          bool allow_change = false) const
         EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
 
     std::set<COutPoint> setLockedCoins GUARDED_BY(cs_wallet);
 
     /** Registered interfaces::Chain::Notifications handler. */
     std::unique_ptr<interfaces::Handler> m_chain_notifications_handler;
 
     /** Interface for accessing chain state. */
     interfaces::Chain &chain() const {
         assert(m_chain);
         return *m_chain;
     }
 
     const CWalletTx *GetWalletTx(const TxId &txid) const
         EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
     bool IsTrusted(const CWalletTx &wtx, std::set<TxId> &trusted_parents) const
         EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
 
     //! check whether we are allowed to upgrade (or already support) to the
     //! named feature
     bool CanSupportFeature(enum WalletFeature wf) const override
         EXCLUSIVE_LOCKS_REQUIRED(cs_wallet) {
         AssertLockHeld(cs_wallet);
         return nWalletMaxVersion >= wf;
     }
 
     /**
      * populate vCoins with vector of available COutputs.
      */
     void AvailableCoins(std::vector<COutput> &vCoins, bool fOnlySafe = true,
                         const CCoinControl *coinControl = nullptr,
                         const Amount nMinimumAmount = SATOSHI,
                         const Amount nMaximumAmount = MAX_MONEY,
                         const Amount nMinimumSumAmount = MAX_MONEY,
                         const uint64_t nMaximumCount = 0) const
         EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
 
     /**
      * Return list of available coins and locked coins grouped by non-change
      * output address.
      */
     std::map<CTxDestination, std::vector<COutput>> ListCoins() const
         EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
 
     /**
      * Find non-change parent output.
      */
     const CTxOut &FindNonChangeParentOutput(const CTransaction &tx,
                                             int output) const
         EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
 
     /**
      * Shuffle and select coins until nTargetValue is reached while avoiding
      * small change; This method is stochastic for some inputs and upon
      * completion the coin set and corresponding actual target value is
      * assembled.
      */
     bool SelectCoinsMinConf(const Amount nTargetValue,
                             const CoinEligibilityFilter &eligibility_filter,
                             std::vector<OutputGroup> groups,
                             std::set<CInputCoin> &setCoinsRet,
                             Amount &nValueRet,
                             const CoinSelectionParams &coin_selection_params,
                             bool &bnb_used) const;
 
     bool IsSpent(const COutPoint &outpoint) const
         EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
 
     // Whether this or any UTXO with the same CTxDestination has been spent.
     bool IsSpentKey(const TxId &txid, unsigned int n) const
         EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
     void SetSpentKeyState(WalletBatch &batch, const TxId &txid, unsigned int n,
                           bool used, std::set<CTxDestination> &tx_destinations)
         EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
 
     std::vector<OutputGroup> GroupOutputs(const std::vector<COutput> &outputs,
                                           bool single_coin,
                                           const size_t max_ancestors) const;
 
     bool IsLockedCoin(const COutPoint &outpoint) const
         EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
     void LockCoin(const COutPoint &output) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
     void UnlockCoin(const COutPoint &output)
         EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
     void UnlockAllCoins() EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
     void ListLockedCoins(std::vector<COutPoint> &vOutpts) const
         EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
 
     /*
      * Rescan abort properties
      */
     void AbortRescan() { fAbortRescan = true; }
     bool IsAbortingRescan() const { return fAbortRescan; }
     bool IsScanning() const { return fScanningWallet; }
     int64_t ScanningDuration() const {
         return fScanningWallet ? GetTimeMillis() - m_scanning_start : 0;
     }
     double ScanningProgress() const {
         return fScanningWallet ? double(m_scanning_progress) : 0;
     }
 
     //! Upgrade stored CKeyMetadata objects to store key origin info as
     //! KeyOriginInfo
     void UpgradeKeyMetadata() EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
 
     bool LoadMinVersion(int nVersion) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet) {
         AssertLockHeld(cs_wallet);
         nWalletVersion = nVersion;
         nWalletMaxVersion = std::max(nWalletMaxVersion, nVersion);
         return true;
     }
 
     /**
      * Adds a destination data tuple to the store, and saves it to disk
      * When adding new fields, take care to consider how DelAddressBook should
      * handle it!
      */
     bool AddDestData(WalletBatch &batch, const CTxDestination &dest,
                      const std::string &key, const std::string &value)
         EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
     //! Erases a destination data tuple in the store and on disk
     bool EraseDestData(WalletBatch &batch, const CTxDestination &dest,
                        const std::string &key)
         EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
     //! Adds a destination data tuple to the store, without saving it to disk
     void LoadDestData(const CTxDestination &dest, const std::string &key,
                       const std::string &value)
         EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
     //! Look up a destination data tuple in the store, return true if found
     //! false otherwise
     bool GetDestData(const CTxDestination &dest, const std::string &key,
                      std::string *value) const
         EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
     //! Get all destination values matching a prefix.
     std::vector<std::string> GetDestValues(const std::string &prefix) const
         EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
 
     //! Holds a timestamp at which point the wallet is scheduled (externally) to
     //! be relocked. Caller must arrange for actual relocking to occur via
     //! Lock().
     int64_t nRelockTime GUARDED_BY(cs_wallet){0};
 
     // Used to prevent concurrent calls to walletpassphrase RPC.
     Mutex m_unlock_mutex;
     bool Unlock(const SecureString &strWalletPassphrase,
                 bool accept_no_keys = false);
     bool ChangeWalletPassphrase(const SecureString &strOldWalletPassphrase,
                                 const SecureString &strNewWalletPassphrase);
     bool EncryptWallet(const SecureString &strWalletPassphrase);
 
     void GetKeyBirthTimes(std::map<CKeyID, int64_t> &mapKeyBirth) const
         EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
     unsigned int ComputeTimeSmart(const CWalletTx &wtx) const;
 
     /**
      * Increment the next transaction order id
      * @return next transaction order id
      */
     int64_t IncOrderPosNext(WalletBatch *batch = nullptr)
         EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
     DBErrors ReorderTransactions();
 
     void MarkDirty();
 
     //! Callback for updating transaction metadata in mapWallet.
     //!
     //! @param wtx - reference to mapWallet transaction to update
     //! @param new_tx - true if wtx is newly inserted, false if it previously
     //! existed
     //!
     //! @return true if wtx is changed and needs to be saved to disk, otherwise
     //! false
     using UpdateWalletTxFn = std::function<bool(CWalletTx &wtx, bool new_tx)>;
 
     CWalletTx *AddToWallet(CTransactionRef tx,
                            const CWalletTx::Confirmation &confirm,
                            const UpdateWalletTxFn &update_wtx = nullptr,
                            bool fFlushOnClose = true);
     bool LoadToWallet(const TxId &txid, const UpdateWalletTxFn &fill_wtx)
         EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
-    void transactionAddedToMempool(const CTransactionRef &tx) override;
+    void transactionAddedToMempool(const CTransactionRef &tx,
+                                   uint64_t mempool_sequence) override;
     void blockConnected(const CBlock &block, int height) override;
     void blockDisconnected(const CBlock &block, int height) override;
     void updatedBlockTip() override;
     int64_t RescanFromTime(int64_t startTime,
                            const WalletRescanReserver &reserver, bool update);
 
     struct ScanResult {
         enum { SUCCESS, FAILURE, USER_ABORT } status = SUCCESS;
 
         //! Hash and height of most recent block that was successfully scanned.
         //! Unset if no blocks were scanned due to read errors or the chain
         //! being empty.
         BlockHash last_scanned_block;
         std::optional<int> last_scanned_height;
 
         //! Hash of the most recent block that could not be scanned due to
         //! read errors or pruning. Will be set if status is FAILURE, unset if
         //! status is SUCCESS, and may or may not be set if status is
         //! USER_ABORT.
         BlockHash last_failed_block;
     };
     ScanResult ScanForWalletTransactions(const BlockHash &start_block,
                                          int start_height,
                                          std::optional<int> max_height,
                                          const WalletRescanReserver &reserver,
                                          bool fUpdate);
     void transactionRemovedFromMempool(const CTransactionRef &tx,
-                                       MemPoolRemovalReason reason) override;
+                                       MemPoolRemovalReason reason,
+                                       uint64_t mempool_sequence) override;
     void ReacceptWalletTransactions() EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
     void ResendWalletTransactions();
     struct Balance {
         //! Trusted, at depth=GetBalance.min_depth or more
         Amount m_mine_trusted{Amount::zero()};
         //! Untrusted, but in mempool (pending)
         Amount m_mine_untrusted_pending{Amount::zero()};
         //! Immature coinbases in the main chain
         Amount m_mine_immature{Amount::zero()};
         Amount m_watchonly_trusted{Amount::zero()};
         Amount m_watchonly_untrusted_pending{Amount::zero()};
         Amount m_watchonly_immature{Amount::zero()};
     };
     Balance GetBalance(int min_depth = 0, bool avoid_reuse = true) const;
     Amount GetAvailableBalance(const CCoinControl *coinControl = nullptr) const;
 
     OutputType
     TransactionChangeType(const std::optional<OutputType> &change_type,
                           const std::vector<CRecipient> &vecSend);
 
     /**
      * Insert additional inputs into the transaction by calling
      * CreateTransaction();
      */
     bool FundTransaction(CMutableTransaction &tx, Amount &nFeeRet,
                          int &nChangePosInOut, bilingual_str &error,
                          bool lockUnspents,
                          const std::set<int> &setSubtractFeeFromOutputs,
                          CCoinControl coinControl);
     // Fetch the inputs and sign with SIGHASH_ALL.
     bool SignTransaction(CMutableTransaction &tx) const
         EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
     // Sign the tx given the input coins and sighash.
     bool SignTransaction(CMutableTransaction &tx,
                          const std::map<COutPoint, Coin> &coins,
                          SigHashType sighash,
                          std::map<int, std::string> &input_errors) const;
     SigningResult SignMessage(const std::string &message, const PKHash &pkhash,
                               std::string &str_sig) const;
 
     /**
      * Fills out a PSBT with information from the wallet. Fills in UTXOs if we
      * have them. Tries to sign if sign=true. Sets `complete` if the PSBT is now
      * complete (i.e. has all required signatures or signature-parts, and is
      * ready to finalize.) Sets `error` and returns false if something goes
      * wrong.
      *
      * @param[in]  psbtx PartiallySignedTransaction to fill in
      * @param[out] complete indicates whether the PSBT is now complete
      * @param[in]  sighash_type the sighash type to use when signing (if PSBT
      * does not specify)
      * @param[in]  sign whether to sign or not
      * @param[in]  bip32derivs whether to fill in bip32 derivation information
      * if available return error
      */
     TransactionError
     FillPSBT(PartiallySignedTransaction &psbtx, bool &complete,
              SigHashType sighash_type = SigHashType().withForkId(),
              bool sign = true, bool bip32derivs = true) const;
 
     /**
      * Create a new transaction paying the recipients with a set of coins
      * selected by SelectCoins(); Also create the change output, when needed
      * @note passing nChangePosInOut as -1 will result in setting a random
      * position
      */
     bool CreateTransaction(const std::vector<CRecipient> &vecSend,
                            CTransactionRef &tx, Amount &nFeeRet,
                            int &nChangePosInOut, bilingual_str &error,
                            const CCoinControl &coin_control, bool sign = true);
 
     /**
      * Submit the transaction to the node's mempool and then relay to peers.
      * Should be called after CreateTransaction unless you want to abort
      * broadcasting the transaction.
      *
      * @param[in] tx The transaction to be broadcast.
      * @param[in] mapValue key-values to be set on the transaction.
      * @param[in] orderForm BIP 70 / BIP 21 order form details to be set on the
      * transaction.
      */
     void CommitTransaction(
         CTransactionRef tx, mapValue_t mapValue,
         std::vector<std::pair<std::string, std::string>> orderForm);
 
     bool DummySignTx(CMutableTransaction &txNew, const std::set<CTxOut> &txouts,
                      bool use_max_sig = false) const {
         std::vector<CTxOut> v_txouts(txouts.size());
         std::copy(txouts.begin(), txouts.end(), v_txouts.begin());
         return DummySignTx(txNew, v_txouts, use_max_sig);
     }
     bool DummySignTx(CMutableTransaction &txNew,
                      const std::vector<CTxOut> &txouts,
                      bool use_max_sig = false) const;
     bool DummySignInput(CTxIn &tx_in, const CTxOut &txout,
                         bool use_max_sig = false) const;
 
     bool ImportScripts(const std::set<CScript> scripts, int64_t timestamp)
         EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
     bool ImportPrivKeys(const std::map<CKeyID, CKey> &privkey_map,
                         const int64_t timestamp)
         EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
     bool ImportPubKeys(
         const std::vector<CKeyID> &ordered_pubkeys,
         const std::map<CKeyID, CPubKey> &pubkey_map,
         const std::map<CKeyID, std::pair<CPubKey, KeyOriginInfo>> &key_origins,
         const bool add_keypool, const bool internal, const int64_t timestamp)
         EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
     bool ImportScriptPubKeys(const std::string &label,
                              const std::set<CScript> &script_pub_keys,
                              const bool have_solving_data,
                              const bool apply_label, const int64_t timestamp)
         EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
 
     CFeeRate m_pay_tx_fee{DEFAULT_PAY_TX_FEE};
     bool m_spend_zero_conf_change{DEFAULT_SPEND_ZEROCONF_CHANGE};
     //! will be false if -fallbackfee=0
     bool m_allow_fallback_fee{true};
     // Override with -mintxfee
     CFeeRate m_min_fee{DEFAULT_TRANSACTION_MINFEE_PER_KB};
     /**
      * If fee estimation does not have enough data to provide estimates, use
      * this fee instead. Has no effect if not using fee estimation Override with
      * -fallbackfee
      */
     CFeeRate m_fallback_fee{DEFAULT_FALLBACK_FEE};
     //! note: this is absolute fee, not fee rate
     Amount m_max_aps_fee{DEFAULT_MAX_AVOIDPARTIALSPEND_FEE};
     OutputType m_default_address_type{DEFAULT_ADDRESS_TYPE};
     /**
      * Default output type for change outputs. When unset, automatically choose
      * type based on address type setting and the types other of non-change
      * outputs (see implementation in CWallet::TransactionChangeType for
      * details).
      */
     std::optional<OutputType> m_default_change_type{};
     /**
      * Absolute maximum transaction fee (in satoshis) used by default for the
      * wallet.
      */
     Amount m_default_max_tx_fee{DEFAULT_TRANSACTION_MAXFEE};
 
     size_t KeypoolCountExternalKeys() const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
     bool TopUpKeyPool(unsigned int kpSize = 0);
 
     int64_t GetOldestKeyPoolTime() const;
 
     std::set<std::set<CTxDestination>> GetAddressGroupings() const
         EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
     std::map<CTxDestination, Amount> GetAddressBalances() const;
 
     std::set<CTxDestination> GetLabelAddresses(const std::string &label) const;
 
     /**
      * Marks all outputs in each one of the destinations dirty, so their cache
      * is reset and does not return outdated information.
      */
     void MarkDestinationsDirty(const std::set<CTxDestination> &destinations)
         EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
 
     bool GetNewDestination(const OutputType type, const std::string label,
                            CTxDestination &dest, std::string &error);
     bool GetNewChangeDestination(const OutputType type, CTxDestination &dest,
                                  std::string &error);
 
     isminetype IsMine(const CTxDestination &dest) const
         EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
     isminetype IsMine(const CScript &script) const
         EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
     isminetype IsMine(const CTxIn &txin) const
         EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
     /**
      * Returns amount of debit if the input matches the filter, otherwise
      * returns 0
      */
     Amount GetDebit(const CTxIn &txin, const isminefilter &filter) const;
     isminetype IsMine(const CTxOut &txout) const
         EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
     ;
     Amount GetCredit(const CTxOut &txout, const isminefilter &filter) const;
     bool IsChange(const CTxOut &txout) const
         EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
     bool IsChange(const CScript &script) const
         EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
     Amount GetChange(const CTxOut &txout) const
         EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
     bool IsMine(const CTransaction &tx) const
         EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
     /** should probably be renamed to IsRelevantToMe */
     bool IsFromMe(const CTransaction &tx) const;
     Amount GetDebit(const CTransaction &tx, const isminefilter &filter) const;
     /** Returns whether all of the inputs match the filter */
     bool IsAllFromMe(const CTransaction &tx, const isminefilter &filter) const;
     Amount GetCredit(const CTransaction &tx, const isminefilter &filter) const;
     Amount GetChange(const CTransaction &tx) const;
     void chainStateFlushed(const CBlockLocator &loc) override;
 
     DBErrors LoadWallet(bool &fFirstRunRet);
     DBErrors ZapSelectTx(std::vector<TxId> &txIdsIn,
                          std::vector<TxId> &txIdsOut)
         EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
 
     bool SetAddressBook(const CTxDestination &address,
                         const std::string &strName, const std::string &purpose);
 
     bool DelAddressBook(const CTxDestination &address);
 
     unsigned int GetKeyPoolSize() const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
 
     //! signify that a particular wallet feature is now used. this may change
     //! nWalletVersion and nWalletMaxVersion if those are lower
     void SetMinVersion(enum WalletFeature, WalletBatch *batch_in = nullptr,
                        bool fExplicit = false) override;
 
     //! change which version we're allowed to upgrade to (note that this does
     //! not immediately imply upgrading to that format)
     bool SetMaxVersion(int nVersion);
 
     //! get the current wallet format (the oldest client version guaranteed to
     //! understand this wallet)
     int GetVersion() const {
         LOCK(cs_wallet);
         return nWalletVersion;
     }
 
     //! Get wallet transactions that conflict with given transaction (spend same
     //! outputs)
     std::set<TxId> GetConflicts(const TxId &txid) const
         EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
 
     //! Check if a given transaction has any of its outputs spent by another
     //! transaction in the wallet
     bool HasWalletSpend(const TxId &txid) const
         EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
 
     //! Flush wallet (bitdb flush)
     void Flush();
 
     //! Close wallet database
     void Close();
 
     /** Wallet is about to be unloaded */
     boost::signals2::signal<void()> NotifyUnload;
 
     /**
      * Address book entry changed.
      * @note called with lock cs_wallet held.
      */
     boost::signals2::signal<void(CWallet *wallet, const CTxDestination &address,
                                  const std::string &label, bool isMine,
                                  const std::string &purpose, ChangeType status)>
         NotifyAddressBookChanged;
 
     /**
      * Wallet transaction added, removed or updated.
      * @note called with lock cs_wallet held.
      */
     boost::signals2::signal<void(CWallet *wallet, const TxId &txid,
                                  ChangeType status)>
         NotifyTransactionChanged;
 
     /** Show progress e.g. for rescan */
     boost::signals2::signal<void(const std::string &title, int nProgress)>
         ShowProgress;
 
     /** Watch-only address added */
     boost::signals2::signal<void(bool fHaveWatchOnly)> NotifyWatchonlyChanged;
 
     /** Keypool has new keys */
     boost::signals2::signal<void()> NotifyCanGetAddressesChanged;
 
     /**
      * Wallet status (encrypted, locked) changed.
      * Note: Called without locks held.
      */
     boost::signals2::signal<void(CWallet *wallet)> NotifyStatusChanged;
 
     /** Inquire whether this wallet broadcasts transactions. */
     bool GetBroadcastTransactions() const { return fBroadcastTransactions; }
     /** Set whether this wallet broadcasts transactions. */
     void SetBroadcastTransactions(bool broadcast) {
         fBroadcastTransactions = broadcast;
     }
 
     /** Return whether transaction can be abandoned */
     bool TransactionCanBeAbandoned(const TxId &txid) const;
 
     /**
      * Mark a transaction (and it in-wallet descendants) as abandoned so its
      * inputs may be respent.
      */
     bool AbandonTransaction(const TxId &txid);
 
     /**
      * Initializes the wallet, returns a new CWallet instance or a null pointer
      * in case of an error.
      */
     static std::shared_ptr<CWallet>
     Create(interfaces::Chain &chain, const std::string &name,
            std::unique_ptr<WalletDatabase> database,
            uint64_t wallet_creation_flags, bilingual_str &error,
            std::vector<bilingual_str> &warnings);
 
     /**
      * Wallet post-init setup
      * Gives the wallet a chance to register repetitive tasks and complete
      * post-init tasks
      */
     void postInitProcess();
 
     bool BackupWallet(const std::string &strDest) const;
 
     /* Returns true if HD is enabled */
     bool IsHDEnabled() const;
 
     /**
      * Returns true if the wallet can give out new addresses. This means it has
      * keys in the keypool or can generate new keys.
      */
     bool CanGetAddresses(bool internal = false) const;
 
     /**
      * Blocks until the wallet state is up-to-date to /at least/ the current
      * chain at the time this function is entered.
      * Obviously holding cs_main/cs_wallet when going into this call may cause
      * deadlock
      */
     void BlockUntilSyncedToCurrentChain() const LOCKS_EXCLUDED(::cs_main)
         EXCLUSIVE_LOCKS_REQUIRED(!cs_wallet);
 
     /**
      * Set a single wallet flag.
      */
     void SetWalletFlag(uint64_t flags);
 
     /**
      * Unsets a single wallet flag.
      */
     void UnsetWalletFlag(uint64_t flag);
 
     /**
      * Check if a certain wallet flag is set.
      */
     bool IsWalletFlagSet(uint64_t flag) const override;
 
     /**
      * Overwrite all flags by the given uint64_t.
      * Returns false if unknown, non-tolerable flags are present.
      */
     bool AddWalletFlags(uint64_t flags);
     /** Loads the flags into the wallet. (used by LoadWallet) */
     bool LoadWalletFlags(uint64_t flags);
 
     /** Determine if we are a legacy wallet */
     bool IsLegacy() const;
 
     /**
      * Returns a bracketed wallet name for displaying in logs, will return
      * [default wallet] if the wallet has no name.
      */
     const std::string GetDisplayName() const override {
         std::string wallet_name =
             GetName().length() == 0 ? "default wallet" : GetName();
         return strprintf("[%s]", wallet_name);
     };
 
     /**
      * Prepends the wallet name in logging output to ease debugging in
      * multi-wallet use cases.
      */
     template <typename... Params>
     void WalletLogPrintf(std::string fmt, Params... parameters) const {
         LogPrintf(("%s " + fmt).c_str(), GetDisplayName(), parameters...);
     };
 
     template <typename... Params>
     void WalletLogPrintfToBeContinued(std::string fmt,
                                       Params... parameters) const {
         LogPrintfToBeContinued(("%s " + fmt).c_str(), GetDisplayName(),
                                parameters...);
     };
 
     /** Upgrade the wallet */
     bool UpgradeWallet(int version, bilingual_str &error,
                        std::vector<bilingual_str> &warnings);
 
     //! Returns all unique ScriptPubKeyMans in m_internal_spk_managers and
     //! m_external_spk_managers
     std::set<ScriptPubKeyMan *> GetActiveScriptPubKeyMans() const;
 
     //! Returns all unique ScriptPubKeyMans
     std::set<ScriptPubKeyMan *> GetAllScriptPubKeyMans() const;
 
     //! Get the ScriptPubKeyMan for the given OutputType and internal/external
     //! chain.
     ScriptPubKeyMan *GetScriptPubKeyMan(const OutputType &type,
                                         bool internal) const;
 
     //! Get the ScriptPubKeyMan for a script
     ScriptPubKeyMan *GetScriptPubKeyMan(const CScript &script) const;
     //! Get the ScriptPubKeyMan by id
     ScriptPubKeyMan *GetScriptPubKeyMan(const uint256 &id) const;
 
     //! Get all of the ScriptPubKeyMans for a script given additional
     //! information in sigdata (populated by e.g. a psbt)
     std::set<ScriptPubKeyMan *>
     GetScriptPubKeyMans(const CScript &script, SignatureData &sigdata) const;
 
     //! Get the SigningProvider for a script
     std::unique_ptr<SigningProvider>
     GetSolvingProvider(const CScript &script) const;
     std::unique_ptr<SigningProvider>
     GetSolvingProvider(const CScript &script, SignatureData &sigdata) const;
 
     //! Get the LegacyScriptPubKeyMan which is used for all types, internal, and
     //! external.
     LegacyScriptPubKeyMan *GetLegacyScriptPubKeyMan() const;
     LegacyScriptPubKeyMan *GetOrCreateLegacyScriptPubKeyMan();
 
     //! Make a LegacyScriptPubKeyMan and set it for all types, internal, and
     //! external.
     void SetupLegacyScriptPubKeyMan();
 
     const CKeyingMaterial &GetEncryptionKey() const override;
     bool HasEncryptionKeys() const override;
 
     /** Get last block processed height */
     int GetLastBlockHeight() const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet) {
         AssertLockHeld(cs_wallet);
         assert(m_last_block_processed_height >= 0);
         return m_last_block_processed_height;
     };
     BlockHash GetLastBlockHash() const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet) {
         AssertLockHeld(cs_wallet);
         assert(m_last_block_processed_height >= 0);
         return m_last_block_processed;
     }
     /** Set last block processed height, currently only use in unit test */
     void SetLastBlockProcessed(int block_height, BlockHash block_hash)
         EXCLUSIVE_LOCKS_REQUIRED(cs_wallet) {
         AssertLockHeld(cs_wallet);
         m_last_block_processed_height = block_height;
         m_last_block_processed = block_hash;
     };
 
     //! Connect the signals from ScriptPubKeyMans to the signals in CWallet
     void ConnectScriptPubKeyManNotifiers();
 
     //! Instantiate a descriptor ScriptPubKeyMan from the WalletDescriptor and
     //! load it
     void LoadDescriptorScriptPubKeyMan(uint256 id, WalletDescriptor &desc);
 
     //! Adds the active ScriptPubKeyMan for the specified type and internal.
     //! Writes it to the wallet file
     //! @param[in] id The unique id for the ScriptPubKeyMan
     //! @param[in] type The OutputType this ScriptPubKeyMan provides addresses
     //!                 for
     //! @param[in] internal Whether this ScriptPubKeyMan provides change
     //!                     addresses
     void AddActiveScriptPubKeyMan(uint256 id, OutputType type, bool internal);
 
     //! Loads an active ScriptPubKeyMan for the specified type and internal.
     //! (used by LoadWallet)
     //! @param[in] id The unique id for the ScriptPubKeyMan
     //! @param[in] type The OutputType this ScriptPubKeyMan provides addresses
     //!                 for
     //! @param[in] internal Whether this ScriptPubKeyMan provides change
     //!                     addresses
     void LoadActiveScriptPubKeyMan(uint256 id, OutputType type, bool internal);
 
     //! Create new DescriptorScriptPubKeyMans and add them to the wallet
     void SetupDescriptorScriptPubKeyMans() EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
 
     //! Return the DescriptorScriptPubKeyMan for a WalletDescriptor if it is
     //! already in the wallet
     DescriptorScriptPubKeyMan *
     GetDescriptorScriptPubKeyMan(const WalletDescriptor &desc) const;
 
     //! Add a descriptor to the wallet, return a ScriptPubKeyMan & associated
     //! output type
     ScriptPubKeyMan *
     AddWalletDescriptor(WalletDescriptor &desc,
                         const FlatSigningProvider &signing_provider,
                         const std::string &label);
 };
 
 /**
  * Called periodically by the schedule thread. Prompts individual wallets to
  * resend their transactions. Actual rebroadcast schedule is managed by the
  * wallets themselves.
  */
 void MaybeResendWalletTxs();
 
 /** RAII object to check and reserve a wallet rescan */
 class WalletRescanReserver {
 private:
     CWallet &m_wallet;
     bool m_could_reserve;
 
 public:
     explicit WalletRescanReserver(CWallet &w)
         : m_wallet(w), m_could_reserve(false) {}
 
     bool reserve() {
         assert(!m_could_reserve);
         if (m_wallet.fScanningWallet.exchange(true)) {
             return false;
         }
         m_wallet.m_scanning_start = GetTimeMillis();
         m_wallet.m_scanning_progress = 0;
         m_could_reserve = true;
         return true;
     }
 
     bool isReserved() const {
         return (m_could_reserve && m_wallet.fScanningWallet);
     }
 
     ~WalletRescanReserver() {
         if (m_could_reserve) {
             m_wallet.fScanningWallet = false;
         }
     }
 };
 
 // Calculate the size of the transaction assuming all signatures are max size
 // Use DummySignatureCreator, which inserts 71 byte signatures everywhere.
 // NOTE: this requires that all inputs must be in mapWallet (eg the tx should
 // be IsAllFromMe).
 int64_t CalculateMaximumSignedTxSize(const CTransaction &tx,
                                      const CWallet *wallet,
                                      bool use_max_sig = false)
     EXCLUSIVE_LOCKS_REQUIRED(wallet->cs_wallet);
 int64_t CalculateMaximumSignedTxSize(const CTransaction &tx,
                                      const CWallet *wallet,
                                      const std::vector<CTxOut> &txouts,
                                      bool use_max_sig = false);
 
 //! Add wallet name to persistent configuration so it will be loaded on startup.
 bool AddWalletSetting(interfaces::Chain &chain, const std::string &wallet_name);
 
 //! Remove wallet name from persistent configuration so it will not be loaded on
 //! startup.
 bool RemoveWalletSetting(interfaces::Chain &chain,
                          const std::string &wallet_name);
 
 #endif // BITCOIN_WALLET_WALLET_H
diff --git a/src/zmq/zmqabstractnotifier.cpp b/src/zmq/zmqabstractnotifier.cpp
index ad9de1df3..b62bba7c3 100644
--- a/src/zmq/zmqabstractnotifier.cpp
+++ b/src/zmq/zmqabstractnotifier.cpp
@@ -1,22 +1,42 @@
 // Copyright (c) 2015 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <zmq/zmqabstractnotifier.h>
 
 #include <cassert>
 
 const int CZMQAbstractNotifier::DEFAULT_ZMQ_SNDHWM;
 
 CZMQAbstractNotifier::~CZMQAbstractNotifier() {
     assert(!psocket);
 }
 
 bool CZMQAbstractNotifier::NotifyBlock(const CBlockIndex * /*CBlockIndex*/) {
     return true;
 }
 
 bool CZMQAbstractNotifier::NotifyTransaction(
     const CTransaction & /*transaction*/) {
     return true;
 }
+
+bool CZMQAbstractNotifier::NotifyBlockConnect(
+    const CBlockIndex * /*CBlockIndex*/) {
+    return true;
+}
+
+bool CZMQAbstractNotifier::NotifyBlockDisconnect(
+    const CBlockIndex * /*CBlockIndex*/) {
+    return true;
+}
+
+bool CZMQAbstractNotifier::NotifyTransactionAcceptance(
+    const CTransaction & /*transaction*/, uint64_t mempool_sequence) {
+    return true;
+}
+
+bool CZMQAbstractNotifier::NotifyTransactionRemoval(
+    const CTransaction & /*transaction*/, uint64_t mempool_sequence) {
+    return true;
+}
diff --git a/src/zmq/zmqabstractnotifier.h b/src/zmq/zmqabstractnotifier.h
index 8dd3c9299..e3c3d851a 100644
--- a/src/zmq/zmqabstractnotifier.h
+++ b/src/zmq/zmqabstractnotifier.h
@@ -1,57 +1,69 @@
 // Copyright (c) 2015 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #ifndef BITCOIN_ZMQ_ZMQABSTRACTNOTIFIER_H
 #define BITCOIN_ZMQ_ZMQABSTRACTNOTIFIER_H
 
 #include <memory>
 #include <string>
 
 class CBlockIndex;
 class CTransaction;
 class CZMQAbstractNotifier;
 
 using CZMQNotifierFactory = std::unique_ptr<CZMQAbstractNotifier> (*)();
 
 class CZMQAbstractNotifier {
 public:
     static const int DEFAULT_ZMQ_SNDHWM{1000};
 
     CZMQAbstractNotifier()
         : psocket(nullptr),
           outbound_message_high_water_mark(DEFAULT_ZMQ_SNDHWM) {}
     virtual ~CZMQAbstractNotifier();
 
     template <typename T>
     static std::unique_ptr<CZMQAbstractNotifier> Create() {
         return std::make_unique<T>();
     }
 
     std::string GetType() const { return type; }
     void SetType(const std::string &t) { type = t; }
     std::string GetAddress() const { return address; }
     void SetAddress(const std::string &a) { address = a; }
     int GetOutboundMessageHighWaterMark() const {
         return outbound_message_high_water_mark;
     }
     void SetOutboundMessageHighWaterMark(const int sndhwm) {
         if (sndhwm >= 0) {
             outbound_message_high_water_mark = sndhwm;
         }
     }
 
     virtual bool Initialize(void *pcontext) = 0;
     virtual void Shutdown() = 0;
 
+    // Notifies of ConnectTip result, i.e., new active tip only
     virtual bool NotifyBlock(const CBlockIndex *pindex);
+    // Notifies of every block connection
+    virtual bool NotifyBlockConnect(const CBlockIndex *pindex);
+    // Notifies of every block disconnection
+    virtual bool NotifyBlockDisconnect(const CBlockIndex *pindex);
+    // Notifies of every mempool acceptance
+    virtual bool NotifyTransactionAcceptance(const CTransaction &transaction,
+                                             uint64_t mempool_sequence);
+    // Notifies of every mempool removal, except inclusion in blocks
+    virtual bool NotifyTransactionRemoval(const CTransaction &transaction,
+                                          uint64_t mempool_sequence);
+    // Notifies of transactions added to mempool or appearing in blocks
     virtual bool NotifyTransaction(const CTransaction &transaction);
 
 protected:
     void *psocket;
     std::string type;
     std::string address;
     int outbound_message_high_water_mark; // aka SNDHWM
 };
 
 #endif // BITCOIN_ZMQ_ZMQABSTRACTNOTIFIER_H
diff --git a/src/zmq/zmqnotificationinterface.cpp b/src/zmq/zmqnotificationinterface.cpp
index 6300edfa6..9296ea3a6 100644
--- a/src/zmq/zmqnotificationinterface.cpp
+++ b/src/zmq/zmqnotificationinterface.cpp
@@ -1,177 +1,208 @@
 // Copyright (c) 2015-2018 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <zmq/zmqnotificationinterface.h>
 #include <zmq/zmqpublishnotifier.h>
 #include <zmq/zmqutil.h>
 
 #include <zmq.h>
 
 #include <primitives/block.h>
 #include <util/system.h>
 
 CZMQNotificationInterface::CZMQNotificationInterface() : pcontext(nullptr) {}
 
 CZMQNotificationInterface::~CZMQNotificationInterface() {
     Shutdown();
 }
 
 std::list<const CZMQAbstractNotifier *>
 CZMQNotificationInterface::GetActiveNotifiers() const {
     std::list<const CZMQAbstractNotifier *> result;
     for (const auto &n : notifiers) {
         result.push_back(n.get());
     }
     return result;
 }
 
 CZMQNotificationInterface *CZMQNotificationInterface::Create() {
     std::map<std::string, CZMQNotifierFactory> factories;
     factories["pubhashblock"] =
         CZMQAbstractNotifier::Create<CZMQPublishHashBlockNotifier>;
     factories["pubhashtx"] =
         CZMQAbstractNotifier::Create<CZMQPublishHashTransactionNotifier>;
     factories["pubrawblock"] =
         CZMQAbstractNotifier::Create<CZMQPublishRawBlockNotifier>;
     factories["pubrawtx"] =
         CZMQAbstractNotifier::Create<CZMQPublishRawTransactionNotifier>;
+    factories["pubsequence"] =
+        CZMQAbstractNotifier::Create<CZMQPublishSequenceNotifier>;
 
     std::list<std::unique_ptr<CZMQAbstractNotifier>> notifiers;
     for (const auto &entry : factories) {
         std::string arg("-zmq" + entry.first);
         if (gArgs.IsArgSet(arg)) {
             const auto &factory = entry.second;
             const std::string address = gArgs.GetArg(arg, "");
             std::unique_ptr<CZMQAbstractNotifier> notifier = factory();
             notifier->SetType(entry.first);
             notifier->SetAddress(address);
             notifier->SetOutboundMessageHighWaterMark(
                 static_cast<int>(gArgs.GetArg(
                     arg + "hwm", CZMQAbstractNotifier::DEFAULT_ZMQ_SNDHWM)));
             notifiers.push_back(std::move(notifier));
         }
     }
 
     if (!notifiers.empty()) {
         std::unique_ptr<CZMQNotificationInterface> notificationInterface(
             new CZMQNotificationInterface());
         notificationInterface->notifiers = std::move(notifiers);
 
         if (notificationInterface->Initialize()) {
             return notificationInterface.release();
         }
     }
 
     return nullptr;
 }
 
 // Called at startup to conditionally set up ZMQ socket(s)
 bool CZMQNotificationInterface::Initialize() {
     int major = 0, minor = 0, patch = 0;
     zmq_version(&major, &minor, &patch);
     LogPrint(BCLog::ZMQ, "zmq: version %d.%d.%d\n", major, minor, patch);
 
     LogPrint(BCLog::ZMQ, "zmq: Initialize notification interface\n");
     assert(!pcontext);
 
     pcontext = zmq_ctx_new();
 
     if (!pcontext) {
         zmqError("Unable to initialize context");
         return false;
     }
 
     for (auto &notifier : notifiers) {
         if (notifier->Initialize(pcontext)) {
             LogPrint(BCLog::ZMQ, "zmq: Notifier %s ready (address = %s)\n",
                      notifier->GetType(), notifier->GetAddress());
         } else {
             LogPrint(BCLog::ZMQ, "zmq: Notifier %s failed (address = %s)\n",
                      notifier->GetType(), notifier->GetAddress());
             return false;
         }
     }
 
     return true;
 }
 
 // Called during shutdown sequence
 void CZMQNotificationInterface::Shutdown() {
     LogPrint(BCLog::ZMQ, "zmq: Shutdown notification interface\n");
     if (pcontext) {
         for (auto &notifier : notifiers) {
             LogPrint(BCLog::ZMQ, "zmq: Shutdown notifier %s at %s\n",
                      notifier->GetType(), notifier->GetAddress());
             notifier->Shutdown();
         }
         zmq_ctx_term(pcontext);
 
         pcontext = nullptr;
     }
 }
 
 namespace {
 
 template <typename Function>
 void TryForEachAndRemoveFailed(
     std::list<std::unique_ptr<CZMQAbstractNotifier>> &notifiers,
     const Function &func) {
     for (auto i = notifiers.begin(); i != notifiers.end();) {
         CZMQAbstractNotifier *notifier = i->get();
         if (func(notifier)) {
             ++i;
         } else {
             notifier->Shutdown();
             i = notifiers.erase(i);
         }
     }
 }
 
 } // anonymous namespace
 
 void CZMQNotificationInterface::UpdatedBlockTip(const CBlockIndex *pindexNew,
                                                 const CBlockIndex *pindexFork,
                                                 bool fInitialDownload) {
     // In IBD or blocks were disconnected without any new ones
     if (fInitialDownload || pindexNew == pindexFork) {
         return;
     }
 
     TryForEachAndRemoveFailed(notifiers,
                               [pindexNew](CZMQAbstractNotifier *notifier) {
                                   return notifier->NotifyBlock(pindexNew);
                               });
 }
 
 void CZMQNotificationInterface::TransactionAddedToMempool(
-    const CTransactionRef &ptx) {
-    // Used by BlockConnected and BlockDisconnected as well, because they're all
-    // the same external callback.
+    const CTransactionRef &ptx, uint64_t mempool_sequence) {
     const CTransaction &tx = *ptx;
 
-    TryForEachAndRemoveFailed(notifiers, [&tx](CZMQAbstractNotifier *notifier) {
-        return notifier->NotifyTransaction(tx);
-    });
+    TryForEachAndRemoveFailed(
+        notifiers, [&tx, mempool_sequence](CZMQAbstractNotifier *notifier) {
+            return notifier->NotifyTransaction(tx) &&
+                   notifier->NotifyTransactionAcceptance(tx, mempool_sequence);
+        });
+}
+
+void CZMQNotificationInterface::TransactionRemovedFromMempool(
+    const CTransactionRef &ptx, MemPoolRemovalReason reason,
+    uint64_t mempool_sequence) {
+    // Called for all non-block inclusion reasons
+    const CTransaction &tx = *ptx;
+
+    TryForEachAndRemoveFailed(
+        notifiers, [&tx, mempool_sequence](CZMQAbstractNotifier *notifier) {
+            return notifier->NotifyTransactionRemoval(tx, mempool_sequence);
+        });
 }
 
 void CZMQNotificationInterface::BlockConnected(
     const std::shared_ptr<const CBlock> &pblock,
     const CBlockIndex *pindexConnected) {
     for (const CTransactionRef &ptx : pblock->vtx) {
-        // Do a normal notify for each transaction added in the block
-        TransactionAddedToMempool(ptx);
+        const CTransaction &tx = *ptx;
+        TryForEachAndRemoveFailed(notifiers,
+                                  [&tx](CZMQAbstractNotifier *notifier) {
+                                      return notifier->NotifyTransaction(tx);
+                                  });
     }
+
+    // Next we notify BlockConnect listeners for *all* blocks
+    TryForEachAndRemoveFailed(
+        notifiers, [pindexConnected](CZMQAbstractNotifier *notifier) {
+            return notifier->NotifyBlockConnect(pindexConnected);
+        });
 }
 
 void CZMQNotificationInterface::BlockDisconnected(
     const std::shared_ptr<const CBlock> &pblock,
     const CBlockIndex *pindexDisconnected) {
     for (const CTransactionRef &ptx : pblock->vtx) {
-        // Do a normal notify for each transaction removed in block
-        // disconnection
-        TransactionAddedToMempool(ptx);
+        const CTransaction &tx = *ptx;
+        TryForEachAndRemoveFailed(notifiers,
+                                  [&tx](CZMQAbstractNotifier *notifier) {
+                                      return notifier->NotifyTransaction(tx);
+                                  });
     }
+
+    // Next we notify BlockDisconnect listeners for *all* blocks
+    TryForEachAndRemoveFailed(
+        notifiers, [pindexDisconnected](CZMQAbstractNotifier *notifier) {
+            return notifier->NotifyBlockDisconnect(pindexDisconnected);
+        });
 }
 
 CZMQNotificationInterface *g_zmq_notification_interface = nullptr;
diff --git a/src/zmq/zmqnotificationinterface.h b/src/zmq/zmqnotificationinterface.h
index e0f3fa371..19878f0ee 100644
--- a/src/zmq/zmqnotificationinterface.h
+++ b/src/zmq/zmqnotificationinterface.h
@@ -1,47 +1,51 @@
 // Copyright (c) 2015-2018 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #ifndef BITCOIN_ZMQ_ZMQNOTIFICATIONINTERFACE_H
 #define BITCOIN_ZMQ_ZMQNOTIFICATIONINTERFACE_H
 
 #include <validationinterface.h>
 
 #include <list>
 #include <memory>
 
 class CBlockIndex;
 class CZMQAbstractNotifier;
 
 class CZMQNotificationInterface final : public CValidationInterface {
 public:
     virtual ~CZMQNotificationInterface();
 
     std::list<const CZMQAbstractNotifier *> GetActiveNotifiers() const;
 
     static CZMQNotificationInterface *Create();
 
 protected:
     bool Initialize();
     void Shutdown();
 
     // CValidationInterface
-    void TransactionAddedToMempool(const CTransactionRef &tx) override;
+    void TransactionAddedToMempool(const CTransactionRef &tx,
+                                   uint64_t mempool_sequence) override;
+    void TransactionRemovedFromMempool(const CTransactionRef &tx,
+                                       MemPoolRemovalReason reason,
+                                       uint64_t mempool_sequence) override;
     void BlockConnected(const std::shared_ptr<const CBlock> &pblock,
                         const CBlockIndex *pindexConnected) override;
     void BlockDisconnected(const std::shared_ptr<const CBlock> &pblock,
                            const CBlockIndex *pindexDisconnected) override;
     void UpdatedBlockTip(const CBlockIndex *pindexNew,
                          const CBlockIndex *pindexFork,
                          bool fInitialDownload) override;
 
 private:
     CZMQNotificationInterface();
 
     void *pcontext;
     std::list<std::unique_ptr<CZMQAbstractNotifier>> notifiers;
 };
 
 extern CZMQNotificationInterface *g_zmq_notification_interface;
 
 #endif // BITCOIN_ZMQ_ZMQNOTIFICATIONINTERFACE_H
diff --git a/src/zmq/zmqpublishnotifier.cpp b/src/zmq/zmqpublishnotifier.cpp
index 3b715d7ff..644c7c6fc 100644
--- a/src/zmq/zmqpublishnotifier.cpp
+++ b/src/zmq/zmqpublishnotifier.cpp
@@ -1,234 +1,294 @@
 // Copyright (c) 2015-2016 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <zmq/zmqpublishnotifier.h>
 
 #include <blockdb.h>
 #include <chain.h>
 #include <chainparams.h>
 #include <config.h>
 #include <primitives/blockhash.h>
 #include <primitives/txid.h>
 #include <rpc/server.h>
 #include <streams.h>
 #include <util/system.h>
 #include <zmq/zmqutil.h>
 
 #include <zmq.h>
 
 #include <cstdarg>
 #include <cstddef>
 #include <map>
 #include <string>
 #include <utility>
 
 static std::multimap<std::string, CZMQAbstractPublishNotifier *>
     mapPublishNotifiers;
 
 static const char *MSG_HASHBLOCK = "hashblock";
 static const char *MSG_HASHTX = "hashtx";
 static const char *MSG_RAWBLOCK = "rawblock";
 static const char *MSG_RAWTX = "rawtx";
+static const char *MSG_SEQUENCE = "sequence";
 
 // Internal function to send multipart message
 static int zmq_send_multipart(void *sock, const void *data, size_t size, ...) {
     va_list args;
     va_start(args, size);
 
     while (1) {
         zmq_msg_t msg;
 
         int rc = zmq_msg_init_size(&msg, size);
         if (rc != 0) {
             zmqError("Unable to initialize ZMQ msg");
             va_end(args);
             return -1;
         }
 
         void *buf = zmq_msg_data(&msg);
         memcpy(buf, data, size);
 
         data = va_arg(args, const void *);
 
         rc = zmq_msg_send(&msg, sock, data ? ZMQ_SNDMORE : 0);
         if (rc == -1) {
             zmqError("Unable to send ZMQ msg");
             zmq_msg_close(&msg);
             va_end(args);
             return -1;
         }
 
         zmq_msg_close(&msg);
 
         if (!data) {
             break;
         }
 
         size = va_arg(args, size_t);
     }
     va_end(args);
     return 0;
 }
 
 bool CZMQAbstractPublishNotifier::Initialize(void *pcontext) {
     assert(!psocket);
 
     // check if address is being used by other publish notifier
     std::multimap<std::string, CZMQAbstractPublishNotifier *>::iterator i =
         mapPublishNotifiers.find(address);
 
     if (i == mapPublishNotifiers.end()) {
         psocket = zmq_socket(pcontext, ZMQ_PUB);
         if (!psocket) {
             zmqError("Failed to create socket");
             return false;
         }
 
         LogPrint(BCLog::ZMQ,
                  "zmq: Outbound message high water mark for %s at %s is %d\n",
                  type, address, outbound_message_high_water_mark);
 
         int rc = zmq_setsockopt(psocket, ZMQ_SNDHWM,
                                 &outbound_message_high_water_mark,
                                 sizeof(outbound_message_high_water_mark));
         if (rc != 0) {
             zmqError("Failed to set outbound message high water mark");
             zmq_close(psocket);
             return false;
         }
 
         const int so_keepalive_option{1};
         rc = zmq_setsockopt(psocket, ZMQ_TCP_KEEPALIVE, &so_keepalive_option,
                             sizeof(so_keepalive_option));
         if (rc != 0) {
             zmqError("Failed to set SO_KEEPALIVE");
             zmq_close(psocket);
             return false;
         }
 
         rc = zmq_bind(psocket, address.c_str());
         if (rc != 0) {
             zmqError("Failed to bind address");
             zmq_close(psocket);
             return false;
         }
 
         // register this notifier for the address, so it can be reused for other
         // publish notifier
         mapPublishNotifiers.insert(std::make_pair(address, this));
         return true;
     } else {
         LogPrint(BCLog::ZMQ, "zmq: Reusing socket for address %s\n", address);
         LogPrint(BCLog::ZMQ,
                  "zmq: Outbound message high water mark for %s at %s is %d\n",
                  type, address, outbound_message_high_water_mark);
 
         psocket = i->second->psocket;
         mapPublishNotifiers.insert(std::make_pair(address, this));
 
         return true;
     }
 }
 
 void CZMQAbstractPublishNotifier::Shutdown() {
     // Early return if Initialize was not called
     if (!psocket) {
         return;
     }
 
     int count = mapPublishNotifiers.count(address);
 
     // remove this notifier from the list of publishers using this address
     typedef std::multimap<std::string, CZMQAbstractPublishNotifier *>::iterator
         iterator;
     std::pair<iterator, iterator> iterpair =
         mapPublishNotifiers.equal_range(address);
 
     for (iterator it = iterpair.first; it != iterpair.second; ++it) {
         if (it->second == this) {
             mapPublishNotifiers.erase(it);
             break;
         }
     }
 
     if (count == 1) {
         LogPrint(BCLog::ZMQ, "zmq: Close socket at address %s\n", address);
         int linger = 0;
         zmq_setsockopt(psocket, ZMQ_LINGER, &linger, sizeof(linger));
         zmq_close(psocket);
     }
 
     psocket = nullptr;
 }
 
 bool CZMQAbstractPublishNotifier::SendZmqMessage(const char *command,
                                                  const void *data,
                                                  size_t size) {
     assert(psocket);
 
     /* send three parts, command & data & a LE 4byte sequence number */
     uint8_t msgseq[sizeof(uint32_t)];
     WriteLE32(&msgseq[0], nSequence);
     int rc = zmq_send_multipart(psocket, command, strlen(command), data, size,
                                 msgseq, (size_t)sizeof(uint32_t), nullptr);
     if (rc == -1) {
         return false;
     }
 
     /* increment memory only sequence number after sending */
     nSequence++;
 
     return true;
 }
 
 bool CZMQPublishHashBlockNotifier::NotifyBlock(const CBlockIndex *pindex) {
     BlockHash hash = pindex->GetBlockHash();
     LogPrint(BCLog::ZMQ, "zmq: Publish hashblock %s\n", hash.GetHex());
     char data[32];
     for (unsigned int i = 0; i < 32; i++) {
         data[31 - i] = hash.begin()[i];
     }
     return SendZmqMessage(MSG_HASHBLOCK, data, 32);
 }
 
 bool CZMQPublishHashTransactionNotifier::NotifyTransaction(
     const CTransaction &transaction) {
     TxId txid = transaction.GetId();
     LogPrint(BCLog::ZMQ, "zmq: Publish hashtx %s\n", txid.GetHex());
     char data[32];
     for (unsigned int i = 0; i < 32; i++) {
         data[31 - i] = txid.begin()[i];
     }
     return SendZmqMessage(MSG_HASHTX, data, 32);
 }
 
 bool CZMQPublishRawBlockNotifier::NotifyBlock(const CBlockIndex *pindex) {
     LogPrint(BCLog::ZMQ, "zmq: Publish rawblock %s\n",
              pindex->GetBlockHash().GetHex());
 
     const Config &config = GetConfig();
     CDataStream ss(SER_NETWORK, PROTOCOL_VERSION | RPCSerializationFlags());
     {
         LOCK(cs_main);
         CBlock block;
         if (!ReadBlockFromDisk(block, pindex,
                                config.GetChainParams().GetConsensus())) {
             zmqError("Can't read block from disk");
             return false;
         }
 
         ss << block;
     }
 
     return SendZmqMessage(MSG_RAWBLOCK, &(*ss.begin()), ss.size());
 }
 
 bool CZMQPublishRawTransactionNotifier::NotifyTransaction(
     const CTransaction &transaction) {
     TxId txid = transaction.GetId();
     LogPrint(BCLog::ZMQ, "zmq: Publish rawtx %s\n", txid.GetHex());
     CDataStream ss(SER_NETWORK, PROTOCOL_VERSION | RPCSerializationFlags());
     ss << transaction;
     return SendZmqMessage(MSG_RAWTX, &(*ss.begin()), ss.size());
 }
+
+// TODO: Dedup this code to take label char, log string
+bool CZMQPublishSequenceNotifier::NotifyBlockConnect(
+    const CBlockIndex *pindex) {
+    BlockHash hash = pindex->GetBlockHash();
+    LogPrint(BCLog::ZMQ, "zmq: Publish sequence block connect %s\n",
+             hash.GetHex());
+    char data[sizeof(BlockHash) + 1];
+    for (unsigned int i = 0; i < sizeof(BlockHash); i++) {
+        data[sizeof(BlockHash) - 1 - i] = hash.begin()[i];
+    }
+    // Block (C)onnect
+    data[sizeof(data) - 1] = 'C';
+    return SendZmqMessage(MSG_SEQUENCE, data, sizeof(data));
+}
+
+bool CZMQPublishSequenceNotifier::NotifyBlockDisconnect(
+    const CBlockIndex *pindex) {
+    BlockHash hash = pindex->GetBlockHash();
+    LogPrint(BCLog::ZMQ, "zmq: Publish sequence block disconnect %s\n",
+             hash.GetHex());
+    char data[sizeof(BlockHash) + 1];
+    for (unsigned int i = 0; i < sizeof(BlockHash); i++) {
+        data[sizeof(BlockHash) - 1 - i] = hash.begin()[i];
+    }
+    // Block (D)isconnect
+    data[sizeof(data) - 1] = 'D';
+    return SendZmqMessage(MSG_SEQUENCE, data, sizeof(data));
+}
+
+bool CZMQPublishSequenceNotifier::NotifyTransactionAcceptance(
+    const CTransaction &transaction, uint64_t mempool_sequence) {
+    TxId txid = transaction.GetId();
+    LogPrint(BCLog::ZMQ, "zmq: Publish hashtx mempool acceptance %s\n",
+             txid.GetHex());
+    uint8_t data[sizeof(TxId) + sizeof(mempool_sequence) + 1];
+    for (unsigned int i = 0; i < sizeof(TxId); i++) {
+        data[sizeof(TxId) - 1 - i] = txid.begin()[i];
+    }
+    // Mempool (A)cceptance
+    data[sizeof(TxId)] = 'A';
+    WriteLE64(data + sizeof(TxId) + 1, mempool_sequence);
+    return SendZmqMessage(MSG_SEQUENCE, data, sizeof(data));
+}
+
+bool CZMQPublishSequenceNotifier::NotifyTransactionRemoval(
+    const CTransaction &transaction, uint64_t mempool_sequence) {
+    TxId txid = transaction.GetId();
+    LogPrint(BCLog::ZMQ, "zmq: Publish hashtx mempool removal %s\n",
+             txid.GetHex());
+    uint8_t data[sizeof(TxId) + sizeof(mempool_sequence) + 1];
+    for (unsigned int i = 0; i < sizeof(TxId); i++) {
+        data[sizeof(TxId) - 1 - i] = txid.begin()[i];
+    }
+    // Mempool (R)emoval
+    data[sizeof(TxId)] = 'R';
+    WriteLE64(data + sizeof(TxId) + 1, mempool_sequence);
+    return SendZmqMessage(MSG_SEQUENCE, data, sizeof(data));
+}
diff --git a/src/zmq/zmqpublishnotifier.h b/src/zmq/zmqpublishnotifier.h
index e9091ad4b..1a7b483a8 100644
--- a/src/zmq/zmqpublishnotifier.h
+++ b/src/zmq/zmqpublishnotifier.h
@@ -1,50 +1,60 @@
 // Copyright (c) 2015-2016 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #ifndef BITCOIN_ZMQ_ZMQPUBLISHNOTIFIER_H
 #define BITCOIN_ZMQ_ZMQPUBLISHNOTIFIER_H
 
 #include <zmq/zmqabstractnotifier.h>
 
 class CBlockIndex;
 
 class CZMQAbstractPublishNotifier : public CZMQAbstractNotifier {
 private:
     //! upcounting per message sequence number
     uint32_t nSequence{0U};
 
 public:
     /* send zmq multipart message
        parts:
           * command
           * data
           * message sequence number
     */
     bool SendZmqMessage(const char *command, const void *data, size_t size);
 
     bool Initialize(void *pcontext) override;
     void Shutdown() override;
 };
 
 class CZMQPublishHashBlockNotifier : public CZMQAbstractPublishNotifier {
 public:
     bool NotifyBlock(const CBlockIndex *pindex) override;
 };
 
 class CZMQPublishHashTransactionNotifier : public CZMQAbstractPublishNotifier {
 public:
     bool NotifyTransaction(const CTransaction &transaction) override;
 };
 
 class CZMQPublishRawBlockNotifier : public CZMQAbstractPublishNotifier {
 public:
     bool NotifyBlock(const CBlockIndex *pindex) override;
 };
 
 class CZMQPublishRawTransactionNotifier : public CZMQAbstractPublishNotifier {
 public:
     bool NotifyTransaction(const CTransaction &transaction) override;
 };
 
+class CZMQPublishSequenceNotifier : public CZMQAbstractPublishNotifier {
+public:
+    bool NotifyBlockConnect(const CBlockIndex *pindex) override;
+    bool NotifyBlockDisconnect(const CBlockIndex *pindex) override;
+    bool NotifyTransactionAcceptance(const CTransaction &transaction,
+                                     uint64_t mempool_sequence) override;
+    bool NotifyTransactionRemoval(const CTransaction &transaction,
+                                  uint64_t mempool_sequence) override;
+};
+
 #endif // BITCOIN_ZMQ_ZMQPUBLISHNOTIFIER_H
diff --git a/test/lint/check-doc.py b/test/lint/check-doc.py
index ef7b50fbc..da87d79cc 100755
--- a/test/lint/check-doc.py
+++ b/test/lint/check-doc.py
@@ -1,96 +1,98 @@
 #!/usr/bin/env python3
 # Copyright (c) 2015-2019 The Bitcoin Core developers
 # Copyright (c) 2019 The Bitcoin developers
 # Distributed under the MIT software license, see the accompanying
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 '''
 This checks if all command line args are documented.
 Return value is 0 to indicate no error.
 
 Author: @MarcoFalke
 '''
 
 import glob
 import re
 from pprint import PrettyPrinter
 from subprocess import check_output
 
 TOP_LEVEL = 'git rev-parse --show-toplevel'
 FOLDER_SRC = '/src/**/'
 FOLDER_TEST = '/src/**/test/'
 
 EXTENSIONS = ["*.c", "*.h", "*.cpp", "*.cc", "*.hpp"]
 REGEX_ARG = r'(?:ForceSet|SoftSet|Get|Is)(?:Bool)?Args?(?:Set)?\(\s*"(-[^"]+)"'
 REGEX_DOC = r'AddArg\(\s*"(-[^"=]+?)(?:=|")'
 
 # list false positive unknows arguments
 SET_FALSE_POSITIVE_UNKNOWNS = set([
     '-includeconf',
     '-regtest',
     '-testnet',
     '-zmqpubhashblock',
     '-zmqpubhashtx',
     '-zmqpubrawblock',
     '-zmqpubrawtx',
     '-zmqpubhashblockhwm',
     '-zmqpubhashtxhwm',
     '-zmqpubrawblockhwm',
     '-zmqpubrawtxhwm',
+    '-zmqpubsequence',
+    '-zmqpubsequencehwm',
 ])
 
 # list false positive undocumented arguments
 SET_FALSE_POSITIVE_UNDOCUMENTED = set([
     '-help',
     '-h',
     '-dbcrashratio',
     '-enableminerfund',
     '-forcecompactdb',
     '-parkdeepreorg',
     '-automaticunparking',
     # Removed arguments that now just print a helpful error message
     '-zapwallettxes',
     # Remove after November 2020 upgrade
     '-axionactivationtime',
     '-replayprotectionactivationtime',
 ])
 
 
 def main():
     top_level = check_output(TOP_LEVEL, shell=True,
                              universal_newlines=True, encoding='utf8').strip()
     source_files = []
     test_files = []
 
     for extension in EXTENSIONS:
         source_files += glob.glob(top_level +
                                   FOLDER_SRC + extension, recursive=True)
         test_files += glob.glob(top_level + FOLDER_TEST +
                                 extension, recursive=True)
 
     files = set(source_files) - set(test_files)
 
     args_used = set()
     args_docd = set()
     for file in files:
         with open(file, 'r', encoding='utf-8') as f:
             content = f.read()
             args_used |= set(re.findall(re.compile(REGEX_ARG), content))
             args_docd |= set(re.findall(re.compile(REGEX_DOC), content))
 
     args_used |= SET_FALSE_POSITIVE_UNKNOWNS
     args_docd |= SET_FALSE_POSITIVE_UNDOCUMENTED
     args_need_doc = args_used - args_docd
     args_unknown = args_docd - args_used
 
     pp = PrettyPrinter()
     print("Args used        : {}".format(len(args_used)))
     print("Args documented  : {}".format(len(args_docd)))
     print("Args undocumented: {}".format(len(args_need_doc)))
     pp.pprint(args_need_doc)
     print("Args unknown     : {}".format(len(args_unknown)))
     pp.pprint(args_unknown)
 
 
 if __name__ == "__main__":
     main()